v3.25.3
Investments, at Fair Value - Schedule of Investments at Fair Value (Details) - USD ($)
$ in Thousands
Sep. 30, 2025
Dec. 31, 2024
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Money market cash equivalents $ 16,984 $ 7,561
Totals 83,099 91,467
Total Liabilities (39) (32)
Total investments, at fair value 83,060 91,435
Level 1    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Money market cash equivalents 16,984 7,561
Totals 62,345 70,988
Total Liabilities (39) (32)
Total investments, at fair value 62,306 70,956
Level 2    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Totals 20,754 20,479
Total investments, at fair value 20,754 20,479
Texas Pacific Land Corporation    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Totals 53,867 63,797
Texas Pacific Land Corporation | Level 1    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Totals 53,867 63,797
Kinetics Market Opportunities Fund    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Totals 8,714 8,302
Kinetics Market Opportunities Fund | Level 2    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Totals 8,714 8,302
Kinetics Mutual Funds and ETFs    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Totals 2,497 2,419
Kinetics Mutual Funds and ETFs | Level 2    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Totals 2,497 2,419
Kinetics Spin-Off and Corporate Restructuring Fund-Institutional Class    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Totals 3,240 3,598
Kinetics Spin-Off and Corporate Restructuring Fund-Institutional Class | Level 2    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Totals 3,240 3,598
Kinetics Global Fund No Load Class    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Totals 2,643 2,416
Kinetics Global Fund No Load Class | Level 2    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Totals 2,643 2,416
All Other Market Traded Equity Securities    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Totals 3,225 2,900
All Other Market Traded Equity Securities | Level 1    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Totals 3,225 2,900
CBOE Global Markets    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Totals 2,378 1,921
CBOE Global Markets | Level 1    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Totals 2,378 1,921
FRMO Corporation    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Totals 1,726 1,916
FRMO Corporation | Level 2    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Totals 1,726 1,916
Grayscale Bitcoin Trust    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Totals 2,875 2,370
Grayscale Bitcoin Trust | Level 1    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Totals 2,875 2,370
Horizon Kinetics SPAC Active ETF    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Totals 1,934 1,828
Horizon Kinetics SPAC Active ETF | Level 2    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Totals 1,934 1,828
Market Traded Equity Securities - Sold Short    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Total Liabilities (39) (32)
Market Traded Equity Securities - Sold Short | Level 1    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Total Liabilities $ (39) $ (32)