SIGNIFICANT ACCOUNTING POLICIES - Restricted Bank Stock (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Changes in accumulated other comprehensive income (loss) by component, net of tax
Restricted bank stock	$ 68.1	$ 43.9
Investment in FHLB stock	8.9	6.0
Bankers’ Bank of the West Bancorp, Inc. bank stock	0.0
Federal Reserve Bank
Changes in accumulated other comprehensive income (loss) by component, net of tax
Restricted cash	$ 68.1	$ 43.9