CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Net income	$ 96,094	$ 152,556	$ 103,996
Other comprehensive income (loss):
Change in net unrealized gain (loss) during the period	10,355	(138,630)	(28,865)
Reclassification adjustment for net losses (gains) included in net (loss) gain on sale of securities and other assets	1,447		(1,207)
Accretion of net unrealized loss on securities transferred to held-to-maturity	3,142	2,953
Change in pension and other postretirement obligations:
Reclassification adjustment for expense included in other expense	(1,547)	(3,715)	(1,092)
Reclassification adjustment for curtailment loss			1,543
Change in the net actuarial (loss) gain	(190)	(2,062)	6,563
Change in unrealized gain (loss) on derivatives:
Change in net unrealized (loss) gain during the period	(11,782)	14,412	5,277
Reclassification adjustment for loss included in loss on termination of derivatives			(16,505)
Reclassification adjustment for expense included in interest expense	2,092	(1,621)	940
Other comprehensive income (loss) before income taxes	3,517	(128,663)	(336)
Deferred tax expense (benefit)	717	(40,465)	(79)
Total other comprehensive income (loss), net of tax	2,800	(88,198)	(257)
Total comprehensive income	$ 98,894	$ 64,358	$ 103,739