CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Statement of Comprehensive Income [Abstract]
Net income	$ 31,882	$ 25,978	$ 79,538	$ 74,443
Available-for-sale investment securities:
Gross unrealized holding loss arising during the period	(34,330)	(57,911)	(26,002)	(172,195)
Related tax benefit	7,671	13,484	6,178	40,170
Reclassification adjustment for net loss (gain) included in net income	7	(21)	2,108	(107)
Related tax benefit (expense)	3	5	(492)	25
Net effect on other comprehensive loss	(26,649)	(44,443)	(18,208)	(132,107)
Defined benefit plan:
Net (loss) gain arising during the period	(244)	203	(244)	264
Related tax benefit (expense)	57	(48)	57	(62)
Amortization of unrecognized loss and service cost on benefit plans	0	23	9	61
Related tax benefit	0	(5)	(2)	(14)
Reclassification from accumulated other comprehensive income ("AOCI")	2,424	139	2,424	139
Related tax benefit	(566)	(32)	(566)	(32)
Net effect on other comprehensive loss	1,671	280	1,678	356
Cash flow hedges:
Net gain (loss) arising during the period	118	3,388	(165)	10,948
Related tax (expense) benefit	(16)	(789)	35	(2,501)
Net effect on other comprehensive loss	102	2,599	(130)	8,447
Total other comprehensive loss, net of tax	(24,876)	(41,564)	(16,660)	(123,304)
Total comprehensive income (loss)	$ 7,006	$ (15,586)	$ 62,878	$ (48,861)