Note 14 - Segment Reporting - Long-lived Assets By Country (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Total long-lived assets	$ 3,470.6	$ 3,556.0
UNITED STATES
Total long-lived assets	2,341.9	2,455.7
UNITED KINGDOM
Total long-lived assets	630.5	597.9
Other Countries [Member]
Total long-lived assets	$ 498.2	$ 502.4

Long-lived assets other than financial instruments, long-term customer relationships of a financial institution, mortgage and other servicing rights, deferred policy acquisition costs, and deferred tax assets.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 41
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-41

Name:	us-gaap_NoncurrentAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant