PARENT COMPANY STATEMENTS - Condensed Statements of Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Dividends from subsidiaries:
Gain on debt extinguishment	$ 242	$ 0	$ 0
Expenses:
Interest on borrowings	0	0	293
Other expenses	34,278	23,369	18,500
Income before tax benefit and equity in undistributed net income of subsidiaries	168,231	240,314	241,348
Income tax benefit	(36,307)	(52,233)	(51,654)
Net Income (Loss)	131,924	188,081	189,694
Other comprehensive (loss) income, net of tax:
Changes in other comprehensive income (loss) related to pension and other post retirement obligations	4,097	(15,831)	13,403
Other comprehensive income (loss)	129,547	(635,812)	(112,704)
Comprehensive income (loss)	261,471	(447,731)	76,990
Parent Company
Dividends from subsidiaries:
Bank subsidiary	89,500	53,000	125,000
Non-bank subsidiaries	10,000	55,000	14,000
Interest and dividends on investments	343	342	245
Gain on debt extinguishment	242	0	0
Total revenues	100,085	108,342	139,245
Expenses:
Interest on borrowings	38	153	446
Other expenses	6,877	6,091	5,717
Total expenses	6,915	6,244	6,163
Income before tax benefit and equity in undistributed net income of subsidiaries	93,170	102,098	133,082
Income tax benefit	2,227	2,942	3,964
Income before equity in undistributed net income of subsidiaries	95,397	105,040	137,046
Equity in undistributed net income of subsidiaries	36,527	83,041	52,648
Net Income (Loss)	131,924	188,081	189,694
Other comprehensive (loss) income, net of tax:
Changes in other comprehensive income (loss) related to pension and other post retirement obligations	4,097	(15,831)	13,403
Changes in other comprehensive (loss) income related to unrealized (losses) gains on investment securities	125,450	(619,981)	(126,107)
Other comprehensive income (loss)	129,547	(635,812)	(112,704)
Comprehensive income (loss)	$ 261,471	$ (447,731)	$ 76,990