TERM DEBT (Narrative) (Details)		12 Months Ended
	Sep. 08, 2021 USD ($)	Dec. 31, 2023 USD ($) subsidiary	Dec. 31, 2022 USD ($)	Dec. 17, 2014 USD ($)
Debt Instrument [Line Items]
Long-term debt		$ 372,396,000	$ 371,753,000
FHLB stock, required collateral		25,800,000	10,900,000
Additional collateral, aggregate fair value		11,946,079,000	11,318,869,000
FHLB borrowing capacity		$ 629,900,000
Number of wholly-owned trust subsidiaries that issue preferred securities | subsidiary		15
Subordinated notes qualified as Tier 2 capital		$ 223,000,000
Asset Pledged as Collateral without Right | Advances from the FHLB
Debt Instrument [Line Items]
Additional collateral, aggregate fair value		2,070,000,000.00	4,000,000,000
Tier 2
Debt Instrument [Line Items]
Subordinated notes qualified as Tier 2 capital		148,200,000
Trust preferred securities
Debt Instrument [Line Items]
Long-term debt		149,288,000	148,284,000
Deferred issuance costs		0	40,000
Contracts payable for purchase of real estate and other assets
Debt Instrument [Line Items]
Long-term debt		80,000	82,000
Debt issued				$ 75,000,000
Debt discount				$ 1,100,000
Stated interest rate (as a percent)				5.75%
Contracts payable for purchase of real estate and other assets | Subordinated Notes 2021
Debt Instrument [Line Items]
Deferred issuance costs		392,000	443,000
Debt issued	$ 150,000,000
Debt discount	$ 1,900,000
Stated interest rate (as a percent)	2.75%
Basis spread on variable rate (as a percent)	2.10%
Contracts payable for purchase of real estate and other assets | Other Assets
Debt Instrument [Line Items]
Unamortized debt issuance expense		$ 38,000	$ 76,000