Accounting Changes And Error Corrections [Abstract] Accounting Changes and Error Corrections [Abstract] Accounting Policies [Abstract] Accounting Policies [Abstract] Accounts Payable Current Accounts payable Accounts payable, Carrying Amount Accounts Payable Fair Value Disclosure Accounts payable, Fair Value Accumulated Defined Benefit Plans Adjustment [Member] Benefit Plan Liabilities [Member] Accumulated Depreciation Depletion And Amortization Property Plant And Equipment Less: Accumulated depreciation Accumulated Net Unrealized Investment Gain Loss [Member] Unrealized Gain (Loss) on Available- For-Sale Investments [Member] Accumulated Other Comprehensive Income Loss [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income Loss Net Of Tax Accumulated other comprehensive income (loss) net of tax, ending balance Accumulated other comprehensive income (loss) net of tax, beginning balance Accumulated other comprehensive loss Accumulated Other Comprehensive Income Loss [Table] Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Translation Adjustment [Member] Foreign Currency Translation [Member] Acofran. Acofran [Member] Acofran [Member] Additional amount to be borrowed Additional Amount To Be Borrowed Additional amount to be borrowed Additional Paid In Capital Common Stock Capital in excess of par value Additional Paid In Capital [Member] Capital in Excess of Par Value [Member] Adjustments To Reconcile Net Income Loss To Cash Provided By Used In Operating Activities Net adjustments Adjustments To Reconcile Net Income Loss To Cash Provided By Used In Operating Activities [Abstract] Adjustments to reconcile net income to net cash provided by operating activities: Advisory Agreement Termination Date Advisory Agreement Termination Date Termination of advisory services, approval date Advisory Agreement Termination Fee Advisory Agreement Termination Fee Advisory agreement termination fee Allowance For Doubtful Accounts Receivable Current Receivables, provision for allowances, claims and doubtful accounts Aluminum flat. Aluminum Flat [Member] Aluminum Flat [Member] Aluminum long. Aluminum Long [Member] Aluminum Long [Member] Aluminum plate. Aluminum Plate [Member] Aluminum Plate [Member] Aluminum price swaps. Aluminum Price Swaps [Member] Aluminum Price Swaps [Member] Amendment Flag Amendment Flag Annual related party monitoring fee maximum. Annual Related Party Monitoring Fee Maximum Annual related party advisory fee maximum Asset Impairment Charges Impairment charges on fixed assets and goodwill Assets Total assets Assets [Abstract] Assets Assets Current Total current assets Assets Current [Abstract] Current assets: Assets Held For Sale Current Assets held for sale Prepaid expenses and other current assets - assets held for sale Available For Sale Equity Securities Amortized Cost Basis Cost Available For Sale Equity Securities Gross Unrealized Gain Gross Unrealized Gains Available For Sale Equity Securities Gross Unrealized Loss Gross Unrealized Losses Available For Sale Securities Fair Value Prepaid and other current assets Availableforsale Securities [Member] Common stock - available-for-sale investment [Member] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Base rate and Canadian prime rate. Base Rate And Canadian Prime Rate [Member] Base Rate and Canadian Prime Rate [Member] Canadian Subsidiaries [Member] Canadian Subsidiaries [Member] Canadian Subsidiaries [Member] Capital Lease Obligations Incurred Asset additions under capital leases Carbon steel flat. Carbon Steel Flat [Member] Carbon Steel Flat [Member] Carbon steel long. Carbon Steel Long [Member] Carbon Steel Long [Member] Carbon steel plate. Carbon Steel Plate [Member] Carbon Steel Plate [Member] Carrying Reported Amount Fair Value Disclosure [Member] Carrying Amount [Member] Cash And Cash Equivalents At Carrying Value Cash and cash equivalents-end of period Cash and cash equivalents-beginning of period Cash and cash equivalents Cash and cash equivalents, Carrying Amount Cash And Cash Equivalents Fair Value Disclosure Cash and cash equivalents, Fair Value Cash equivalents Cash And Cash Equivalents Period Increase Decrease Net change in cash and cash equivalents Cash And Cash Equivalents Period Increase Decrease Excluding Exchange Rate Effect Net increase in cash and cash equivalents Change Of Control Event [Member] Change Of Control Event [Member] Change Of Control Event [Member] Commercial Paper [Member] Commercial Paper [Member] Commitments And Contingencies Commitments and contingencies Commitments And Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Commitments And Contingencies Disclosure [Text Block] COMMITMENTS AND CONTINGENCIES Commodity Contract [Member] Commodity contracts [Member] Common Stock [Member] Common Stock [Member] Common Stock Par Or Stated Value Per Share Common stock, par value Common Stock Shares Authorized Common stock, shares authorized Common Stock Shares Issued Common stock, shares issued Common Stock Value Common stock, value Compensation And Retirement Disclosure [Abstract] Compensation and Retirement Disclosure [Abstract] Compensation Expense Recognized Upon IPO Compensation Expense Recognized Upon Ipo Compensation expense associated with the initial public offering Comprehensive Income Net Of Tax Comprehensive income (loss) attributable to Ryerson Holding Corporation Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest Less: Comprehensive loss attributable to noncontrolling interest Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest Comprehensive income (loss) Cost Of Goods Sold Cost of materials sold Cost Of Sales [Member] Cost of Sales [Member] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] The cash outflow paid to third parties in connection with credit facility amendments, which will be amortized over the remaining maturity period of the associated credit facility. Credit Facility Issuance Costs Credit facility issuance costs Current Fiscal Year End Date Current Fiscal Year End Date Debt Disclosure [Abstract] Debt Disclosure [Abstract] Debt Disclosure [Text Block] LONG-TERM DEBT Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument Basis Spread On Variable Rate 1 Percentage of spread over amount available to be borrowed Debt Instrument Face Amount Aggregate amount of senior notes issued Debt Instrument Fair Value Long-term debt, including current portion, Fair Value Debt Instrument Interest Rate Stated Percentage Debt Instrument Percentage Debt Instrument [Line Items] Debt Instrument [Line Items] Debt Instrument Name [Domain] Debt Instrument, Name [Domain] The percent of the principal amount of the notes, at which the Company may redeem a portion of the notes prior to the debt instrument redemption date with net cash proceeds from certain equity offerings. Debt Instrument Optional Redemption Price Percentage Redemption price as a percentage of principal amount Prior to Redemption date Debt Instrument Principal Amount To Redeemed Debt Instrument Principal Amount To Redeemed Redemption in principal amount The percentage of the principal amount at which, the 2017 and 2018 notes are redeemable prior to the redemption date, together with accrued and unpaid interest, if any, to the redemption date, plus a make-whole premium. Debt Instruments Early Redemption Price As Percentage Of Principal Amount Redemption price as a percentage of principal amount The date on or after which the notes will become redeemable by the Company, in whole or in part, at specified redemption prices. Debt Instruments Redemption Date Notes redemption date The percentage of the principal amount at which, the 2017 and 2018 notes are redeemable prior to the redemption date, together with accrued and unpaid interest. Debt Instruments Redemption Price As Percentage Of Principal Amount Redemption price as a percentage of principal amount Debt Instrument [Table] Schedule of Long-term Debt Instruments [Table] Debt Longterm And Shortterm Combined Amount Long-term debt, including current portion, Carrying Amount Total debt Debt Weighted Average Interest Rate Weighted average interest rate Deferred Income Tax Expense Benefit Deferred income taxes Deferred Tax Assets Net Noncurrent Deferred income taxes Deferred Tax Assets Valuation Allowance Valuation allowance Deferred Tax Liabilities Current Deferred income taxes Defined Benefit Plan Actuarial Gain Loss Recognized actuarial net (gain) loss Defined Benefit Plan Amortization Of Prior Service Cost Credit Prior service credit Defined Benefit Plan Expected Return On Plan Assets Expected return on assets Defined Benefit Plan Interest Cost Interest cost Defined Benefit Plan Net Periodic Benefit Cost Net periodic benefit cost (credit) Defined Benefit Plans And Other Postretirement Benefit Plans Disclosures [Table] Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table] Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items] Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] Defined Benefit Plans Disclosures Defined Benefit Plans [Axis] Defined Benefit Plans and Other Postretirement Benefit Plans [Axis] Defined Benefit Plans [Domain] Defined Benefit Plan and Other Postretirement Benefit Plan [Domain] Defined Benefit Plan Service Cost Service cost Defined Benefit Plans Estimated Future Employer Contributions In Current Fiscal Year Anticipated minimum required pension contribution funding Depreciation Depletion And Amortization Depreciation and amortization Derivative Assets Asset Derivatives, Fair Value Mark-to-market derivatives Derivative Contract Type [Domain] Derivative Contract [Domain] Derivative Gain Loss On Derivative Net Amount of Gain/ (Loss) Recognized in Income on Derivatives, Total Derivative Instrument Risk [Axis] Derivative Instrument [Axis] Derivative Instruments Gain Loss By Hedging Relationship By Income Statement Location By Derivative Instrument Risk [Table] Derivative Instruments, Gain (Loss) [Table] Derivative Instruments Gain Loss [Line Items] Derivative Instruments, Gain (Loss) [Line Items] Derivative Liabilities Liability Derivatives, Fair Value Mark-to-market derivatives Derivative Nonmonetary Notional Amount Mass Commodity notional value Derivative Notional Amount Notional amount of foreign currency exchange contracts Derivatives Fair Value [Line Items] Derivatives, Fair Value [Line Items] Derivative Term Of Contract Contract term for exchange contracts, Maximum Extent of future net income to which the terms of the Ryerson Notes restrict Ryerson from paying dividends to Ryerson Holding. Dividend Payment Threshold Of Percentage Of Future Net Income Maximum percentage of dividend of future net income Document and entity information. Document And Entity Information [Abstract] Document And Entity Information [Abstract] Document Fiscal Period Focus Document Fiscal Period Focus Document Fiscal Year Focus Document Fiscal Year Focus Document Period End Date Document Period End Date Document Type Document Type Earnings Per Share [Abstract] Earnings Per Share [Abstract] Earnings Per Share Basic And Diluted Basic and diluted earnings per share Basic and diluted income per share Earnings Per Share [Text Block] EARNINGS PER SHARE Effect Of Exchange Rate On Cash And Cash Equivalents Effect of exchange rate changes on cash and cash equivalents Eligible Item Or Group For Fair Value Option [Axis] Eligible Item or Group for Fair Value Option [Axis] Employee Related Liabilities Current Salaries, wages and commissions Entity Central Index Key Entity Central Index Key Entity Common Stock Shares Outstanding Entity Common Stock, Shares Outstanding Entity [Domain] Entity [Domain] Entity Filer Category Entity Filer Category Entity Registrant Name Entity Registrant Name Entity Wide Information Revenue From External Customer [Line Items] Revenue from External Customer [Line Items] Equity [Abstract] Equity [Abstract] Equity Component [Domain] Equity Component [Domain] Estimate Of Fair Value Fair Value Disclosure [Member] Fair Value [Member] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Assets Measured On Nonrecurring Basis [Text Block] Assets and Liabilities Measured and Recorded at Fair Value on Non-Recurring Basis Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value By Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Fair Value By Balance Sheet Grouping [Text Block] Carrying and Estimated Fair Values of Financial Instruments Fair Value By Fair Value Hierarchy Level [Axis] Fair Value, Hierarchy [Axis] Fair Value By Measurement Basis [Axis] Measurement Basis [Axis] Fair Value By Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value Disclosure Item Amounts [Domain] Fair Value Measurement [Domain] Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Fair Value Inputs Level 1 [Member] Level 1 [Member] Fair Value Inputs Level 2 [Member] Level 2 [Member] Fair Value Inputs Level 3 [Member] Level 3 [Member] Fair Value Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair Value Measurements Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Fair Value Measurements Nonrecurring [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value Measurements Recurring [Member] Fair Value, Measurements, Recurring [Member] Fair Value Option Eligible Item Or Group [Domain] Fair Value, Option, Eligible Item or Group [Domain] Fair Values Derivatives Balance Sheet Location By Derivative Contract Type By Hedging Designation [Table] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Financial Instruments Disclosure [Text Block] DERIVATIVES AND FAIR VALUE MEASUREMENTS Finite Lived Intangible Assets Net Other intangible assets Foreign debt long term and short term combined amount. Foreign Debt Long Term And Short Term Combined Amount Foreign debt Foreign debt. Foreign Debt [Member] Foreign Debt [Member] Foreign Debt Short Term Amount Foreign Debt Short Term Amount Short-term foreign debt Foreign Exchange Forward [Member] Foreign Exchange Forward [Member] Goodwill Goodwill Goodwill And Intangible Assets Disclosure [Abstract] Goodwill and Intangible Assets Disclosure [Abstract] Goodwill And Intangible Assets Disclosure [Text Block] GOODWILL AND OTHER INTANGIBLE ASSETS Gross Profit Gross profit Hedging Designation [Axis] Hedging Designation [Axis] Hedging Designation [Domain] Hedging Designation [Domain] Hot Roll Steel Coil Option [Member] Hot Roll Steel Coil Option [Member] Hot Roll Steel Coil Option [Member] Impairment Of Long Lived Assets To Be Disposed Of Impairment charge of asset held for sale Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest Total before tax Income before income taxes Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Income Tax Disclosure [Abstract] Income Tax Disclosure [Abstract] Income Tax Disclosure [Text Block] INCOME TAXES Income Taxes Paid Net Income taxes, net Income Tax Expense Benefit Provision for income taxes Tax provision Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance Net Tax Benefits related to changes in valuation allowance Increase Decrease In Accounts Payable Accounts payable Increase Decrease In Accrued Liabilities Accrued liabilities Increase Decrease In Accrued Taxes Payable Accrued taxes payable/receivable Increase Decrease In Book Overdrafts Net increase in book overdrafts Increase Decrease In Inventories Inventories Increase Decrease In Operating Capital [Abstract] Change in operating assets and liabilities: Increase Decrease In Other Operating Capital Net Other items Increase Decrease In Pension And Postretirement Obligations Deferred employee benefit costs Increase Decrease In Prepaid Deferred Expense And Other Assets Other assets Increase Decrease In Receivables Receivables Increase Decrease In Restricted Cash (Increase) decrease in restricted cash Increase Decrease In Stockholders Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Initial Public Offering Issuance Cost Initial Public Offering Issuance Cost Initial public offering cost Interest Expense Interest and other expense on debt Interest Paid Interest paid to third parties Interest Rate on Overdue Amounts and during Default Interest Rate On Overdue Amounts And During Default Default bear interest rate Inventory Disclosure [Abstract] Inventory Disclosure [Abstract] Inventory Disclosure [Text Block] INVENTORIES Inventory L I F O Reserve Amount by which current cost used to value inventories is lower than LIFO valued inventories Inventory Net In process and finished products Inventories Investments All Other Investments [Abstract] Investments, All Other Investments [Abstract] I P O [Member] IPO [Member] Legal Entity [Axis] Legal Entity [Axis] Letters Of Credit Outstanding Amount Letters of credit Letters of credit issued by our foreign subsidiaries Liabilities Total liabilities Liabilities [Abstract] Liabilities Liabilities And Stockholders Equity Total liabilities and equity Liabilities Current Total current liabilities Liabilities Current [Abstract] Current liabilities: LIBOR and Banker's acceptance rate. Libor And Bankers Acceptance Rate [Member] LIBOR and Banker's Acceptance Rate [Member] Line Of Credit Facility [Axis] Lender Name [Axis] Line Of Credit Facility Collateral Line of credit facility, description of collateral Line Of Credit Facility Commitment Fee Percentage Commitment fees on amounts not borrowed Line Of Credit Facility Expiration Date 1 Credit facility maturity date Line of credit facility expiration date description. Line Of Credit Facility Expiration Description Credit facility scenario 2 maturity description of ("2017 Notes") Line Of Credit Facility Lender [Domain] Line of Credit Facility, Lender [Domain] Line Of Credit Facility Maximum Borrowing Capacity Amended and restated credit facility agreement Line Of Credit Facility Remaining Borrowing Capacity Available credit facility Line Of Credit [Member] Line of Credit [Member] Lines Of Credit Current Short-term credit facility borrowings Long Term Debt Noncurrent Long-term debt Total long-term debt Long Term Line Of Credit Outstanding borrowings Ryerson Secured Credit Facility Loss Contingency Damages Awarded Value Total awarded value for damages to plaintiffs Loss Contingency Range Of Possible Loss Maximum Potential loss range maximum Loss Contingency Range Of Possible Loss Minimum Potential loss range minimum Major Types Of Debt And Equity Securities [Axis] Major Types of Debt and Equity Securities [Axis] Major Types Of Debt And Equity Securities [Domain] Major Types of Debt and Equity Securities [Domain] Maximum [Member] Maximum [Member] Minimum [Member] Minimum [Member] Minority Interest Noncontrolling interest Minority Interest Ownership Percentage By Parent Ownership percentage by parent Net Cash Provided By Used In Financing Activities [Abstract] Financing activities: Net Cash Provided By Used In Financing Activities Continuing Operations Net cash provided by (used in) financing activities Net Cash Provided By Used In Investing Activities [Abstract] Investing activities: Net Cash Provided By Used In Investing Activities Continuing Operations Net cash used in investing activities Net Cash Provided By Used In Operating Activities [Abstract] Operating activities: Net Cash Provided By Used In Operating Activities Continuing Operations Net cash provided by operating activities Net Income Loss Net income available to common stockholders Net income attributable to Ryerson Holding Corporation Net Income Loss Attributable To Noncontrolling Interest Less: Net loss attributable to noncontrolling interest Net Income Loss Attributable To Redeemable Noncontrolling Interest Net income (loss) Net Income Loss Including Portion Attributable To Nonredeemable Noncontrolling Interest Net income (loss) New Accounting Pronouncements And Changes In Accounting Principles [Text Block] RECENT ACCOUNTING PRONOUNCEMENTS Nickel Futures Or Option Contracts [Member] Nickel Futures Or Option Contracts [Member] Nickel Futures or Option Contracts [Member] Noncash Investing And Financing Items [Abstract] Noncash investing activities: Noncontrolling Interest [Member] Noncontrolling Interest [Member] Nondesignated [Member] Derivatives not designated as hedging instruments under ASC 815 [Member] Nonoperating Income Expense Other income and (expense), net Offsetting [Abstract] Offsetting [Abstract] Operating Expense [Member] Warehousing Delivery Selling General And Administrative [Member] Operating Expenses Warehousing, delivery, selling, general and administrative Operating Income Loss Operating profit The portion of the notes that the Company may redeem prior to the debt instrument redemption date with net cash proceeds from certain equity offerings. Optional Redemption Prior To Maturity Additional Percentage Of Principal Optional redemption amount prior to redemption date Organization Consolidation And Presentation Of Financial Statements Disclosure [Text Block] FINANCIAL STATEMENTS Other Accrued Liabilities Current Other accrued liabilities Other Accrued Liabilities [Member] Other Accrued Liabilities [Member] Other accrued liabilities [Member] Other Comprehensive Income Loss Amortization Adjustment From A O C I Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Before Tax Prior service credits Other Comprehensive Income Loss Before Reclassifications Net Of Tax Other comprehensive income (loss) before reclassifications Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax Foreign currency translation Other Comprehensive Income Loss Net Of Tax Net current-period other comprehensive income (loss) Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax Changes in defined benefit pension and other post-retirement benefit plans, net of tax provision Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Tax Changes in defined benefit pension and other post-retirement benefit plans, tax Provision Other Comprehensive Income Loss Reclassification Adjustment From A O C I Pension And Other Postretirement Benefit Plans For Net Gain Loss Before Tax Actuarial gain/loss Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax Unrealized loss on available-for-sale investment, net of tax benefit Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax Unrealized loss on available-for-sale investment, tax benefit Other Inventory Materials Supplies And Merchandise Under Consignment Consignment inventory Other Liabilities Noncurrent Taxes and other credits Other Postretirement Benefit Plans Defined Benefit [Member] Other Benefits [Member] Others. Others [Member] Other [Member] Owed to banks. Owed To Banks [Member] Owed to Banks [Member] Parent company percentage owned by affiliates. Parent Company Percentage Owned By Affiliates Parent company percentage owned by affiliates Payments Of Debt Issuance Costs Long-term debt issuance costs Payments To Acquire Productive Assets Capital expenditures Pension And Other Postretirement Benefits Disclosure [Text Block] EMPLOYEE BENEFITS Pension And Other Postretirement Defined Benefit Plans Current Liabilities Current portion of deferred employee benefits Pension And Other Postretirement Defined Benefit Plans Liabilities Noncurrent Deferred employee benefits Pension Contributions Contribution to the pension plan fund Pension Plans Defined Benefit [Member] Pension Benefits [Member] Percentage Of L I F O Inventory Inventories accounted under the LIFO method Percentage of sales by major product lines. Percentage Of Sales By Major Product Lines Percentage of sales by major product lines Prepaid Expense And Other Assets Current Prepaid expenses and other current assets Prepaid Expense And Other Assets Noncurrent Deferred charges and other assets Prepaid Expenses And Other Current Assets [Member] Prepaid expenses and other current assets [Member] Proceeds From Issuance Initial Public Offering Net proceeds from offering Proceeds From Repayments Of Short Term Debt Maturing In Three Months Or Less Net repayments of short term borrowings Proceeds From Sale Of Available For Sale Securities Proceeds from sale of investments Proceeds From Sale Of Property Plant And Equipment Proceeds from sales of property, plant and equipment Product Or Service [Axis] Products and Services [Axis] Products And Services [Domain] Products and Services [Domain] Profit Loss Net income Net income Net of tax Property Plant And Equipment Gross Property, plant, and equipment, at cost Property Plant And Equipment Net Property, plant and equipment, net Provision For Doubtful Accounts Provision for allowances, claims and doubtful accounts Range [Axis] Range [Axis] Range [Member] Range [Domain] Receivables [Abstract] Receivables [Abstract] Receivables Fair Value Disclosure Receivables less provision for allowances, claims and doubtful accounts, Fair Value Receivables Net Current Receivables less provision for allowances, claims and doubtful accounts Receivables less provision for allowances, claims and doubtful accounts, Carrying Amount Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items] Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax Amounts reclassified from accumulated other comprehensive income Reclassification Out Of Accumulated Other Comprehensive Income [Abstract] Reclassification Out Of Accumulated Other Comprehensive Income [Abstract] Reclassification Out Of Accumulated Other Comprehensive Income [Abstract] Reclassification Out Of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification Out Of Accumulated Other Comprehensive Income [Domain] Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification Out Of Accumulated Other Comprehensive Income [Member] Reclassification out of Accumulated Other Comprehensive Income [Member] Reclassification Out Of Accumulated Other Comprehensive Income [Table] Reclassification out of Accumulated Other Comprehensive Income [Table] Reclassification Out Of Accumulated Other Comprehensive Income Table [Text Block] Reclassifications Out of Accumulated Other Comprehensive Income (Loss) Redeemable Noncontrolling Interest Equity Carrying Amount Ending Balance Beginning Balance Redeemable noncontrolling interest Redeemable noncontrolling interest. Redeemable Noncontrolling Interest [Member] Redeemable Non- controlling Interest [Member] Redemption Premium Redemption premium Related Party Transaction Amounts Of Transaction Payment of advisory fee recorded Related Party Transactions [Abstract] Related Party Transactions [Abstract] Related Party Transactions Disclosure [Text Block] RELATED PARTIES Repayments Of Long Term Capital Lease Obligations Principal payments on capital lease obligation Restricted Cash And Cash Equivalents At Carrying Value Restricted cash Restricted Cash, Carrying Amount Restricted Cash Fair Value Disclosure Restricted Cash Fair Value Disclosure Restricted Cash, Fair Value Restructuring And Related Activities [Abstract] Restructuring and Related Activities [Abstract] Restructuring Charges Restructuring and other charges Retained Earnings Accumulated Deficit Accumulated deficit Retained Earnings [Member] Accumulated Deficit [Member] Revolving Credit Facility [Member] Ryerson Secured Credit Facility [Member] Ryerson China [Member] Ryerson China [Member] Ryerson China [Member] Sale Of Stock Name Of Transaction [Domain] Sale of Stock, Name of Transaction [Domain] Sales Revenue Net Net sales Scenario 1 [Member] Scenario 1 [Member] Scenario 1 [Member] Scenario 2 [Member] Scenario 2 [Member] Scenario 2 [Member] Scenario Unspecified [Domain] Scenario, Unspecified [Domain] Schedule Of Accumulated Other Comprehensive Income Loss Table [Text Block] Changes in Accumulated Other Comprehensive Income/(Loss) by Component Schedule Of Available For Sale Securities [Line Items] Schedule of Available-for-sale Securities [Line Items] Schedule Of Available For Sale Securities Reconciliation Table [Text Block] Available-for-sale Securities Schedule Of Available For Sale Securities [Table] Schedule of Available-for-sale Securities [Table] Schedule Of Changes In Accumulated Other Comprehensive Income Loss By Component [Abstract] Schedule Of Changes In Accumulated Other Comprehensive Income Loss By Component [Abstract] Schedule Of Changes In Accumulated Other Comprehensive Income Loss By Component [Abstract] Schedule Of Debt Table [Text Block] Long-Term Debt Schedule Of Derivative Instruments In Statement Of Financial Position Fair Value [Text Block] Location and Fair Value Amount of Derivative Instruments Schedule of derivatives not designated as hedging instruments gain loss in statement of financial performance. Schedule Of Derivatives Not Designated As Hedging Instruments Gain Loss In Statement Of Financial Performance Table [Text Block] Location and Amount of Gains and Losses Reported in Consolidated Statements of Comprehensive Income Schedule Of Earnings Per Share Basic And Diluted Table [Text Block] Calculation of Basic and Diluted Earnings (loss) Per Share Schedule Of Entity Wide Information Revenue From External Customers By Products And Services [Table] Revenue from External Customers by Products and Services [Table] Schedule Of Fair Value Assets And Liabilities Measured On Recurring Basis Table [Text Block] Assets and Liabilities Measured and Recorded at Fair Value Schedule Of Inventory Current Table [Text Block] Schedule of Inventories Schedule Of Net Benefit Costs Table [Text Block] Components of Net Periodic Benefit Cost Schedule Of Product Information Table [Text Block] Percentage of Sales by Major Product Lines Schedule Of Stockholders Equity Table [Text Block] Change in Stockholders' Equity (Deficit), Accumulated Other Comprehensive Income and Redeemable Noncontrolling Interest Senior Notes Senior Notes Shares Issued Ending Balance, shares Beginning Balance, shares Shares Issued Price Per Share Common stock issued per share Short Term Borrowings Short-term debt Short term credit facility borrowings. Short Term Credit Facility Borrowings [Member] Short-term credit facility borrowings [Member] Stainless steel flat. Stainless Steel Flat [Member] Stainless Steel Flat [Member] Stainless steel long. Stainless Steel Long [Member] Stainless Steel Long [Member] Stainless steel plate. Stainless Steel Plate [Member] Stainless Steel Plate [Member] Statement Equity Components [Axis] Equity Components [Axis] Statement Of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Statement Of Financial Position [Abstract] Statement of Financial Position [Abstract] Statement Of Income And Comprehensive Income [Abstract] Statement of Comprehensive Income [Abstract] Statement Scenario [Axis] Scenario [Axis] Stockholders Equity Total Ryerson Holding Corporation stockholders' equity (deficit) Stockholders Equity [Abstract] Ryerson Holding Corporation stockholders' equity (deficit): Stockholders Equity Including Portion Attributable To Noncontrolling Interest Ending Balance Beginning Balance Total equity (deficit) Stockholders Equity Including Portion Attributable To Noncontrolling Interest [Abstract] Equity Stockholders Equity Note Disclosure [Text Block] STOCKHOLDERS' EQUITY (DEFICIT), ACCUMULATED OTHER COMPREHENSIVE INCOME AND REDEEMABLE NONCONTROLLING INTEREST Stockholders Equity Note Stock Split Conversion Ratio 1 Stock split ratio Stock Issued During Period Shares New Issues Common stock issued Stock Split, Approval Date Stock Split Approval Date Stock split, approval date Subsequent Event [Line Items] Subsequent Event [Line Items] Subsequent Event [Member] Subsequent Event [Member] Subsequent Events [Abstract] Subsequent Events [Abstract] Subsequent Events [Text Block] SUBSEQUENT EVENTS Subsequent Event [Table] Subsequent Event [Table] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsidiary Sale Of Stock [Axis] Subsidiary, Sale of Stock [Axis] Summary of Accounting and Financial Policies [Line Items] Summary Of Accounting And Financial Policies [Line Items] Summary of Accounting and Financial Policies [Line Items] Summary of Accounting and Financial Policies [Table] Summary Of Accounting And Financial Policies [Table] Summary of Accounting and Financial Policies [Table] Supplemental Cash Flow Elements [Abstract] Cash paid during the period for: Supplemental Cash Flow Information [Abstract] Supplemental disclosures: Trading Symbol Trading Symbol Treasury Stock [Member] Treasury Stock [Member] Treasury Stock Shares Treasury stock at cost - Common stock, shares Treasury Stock Value Treasury stock at cost - Common stock, value Twenty Seventeen and Twenty Eighteen Notes [Member] Twenty Seventeen And Twenty Eighteen Notes [Member] 2017 and 2018 Notes [Member] Two Thousand And Seventeen Senior Notes [Member] Two Thousand And Seventeen Senior Notes [Member] 2017 Notes [Member] Two Thousand Eighteen Senior Notes [Member] Two Thousand Eighteen Senior Notes [Member] 2018 Notes [Member] US Subsidiaries [Member] Us Subsidiaries [Member] US Subsidiaries [Member] Weighted Average Number Of Share Outstanding Basic And Diluted Average shares of common stock outstanding Write Off Of Deferred Debt Issuance Cost Debt issuance costs associated with the partial redemption Sales By Product Category [Abstract]. Sales By Product Category [Abstract] Sales By Product Category [Abstract]