Consolidated Statements of Comprehensive (Loss) Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 146,936	$ 95,644	$ 81,477
Unrealized (losses) gains on securities available for sale:
Unrealized holding (losses) gains arising during the period, pretax	(411,996)	(53,752)	18,729
Tax benefit (expense)	94,677	12,352	(4,304)
Reclassification to realized losses (gains)	0	1,237	(8,024)
Tax (benefit) expense	0	(284)	1,844
Postretirement plans:
Net gain arising during period	695	872	589
Tax expense	(159)	(201)	(135)
Amortization of unrecognized net actuarial (gain) loss	(288)	592	686
Tax expense (benefit)	66	(136)	(158)
Other comprehensive (loss) income	(317,005)	(39,320)	9,227
Comprehensive (loss) income	$ (170,069)	$ 56,324	$ 90,704