CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Statement of Comprehensive Income [Abstract]
Net income	$ 14,611	$ 25,673	$ 38,889	$ 49,315
Change in available-for-sale and transferred securities:
Unrealized holding gain (loss) on securities available-for-sale arising during the period	(13,511)	(82,609)	13,282	(221,605)
Reclassification adjust for amortization of unrealized losses on securities transferred to held-to-maturity	494	386	985	386
Reclassification adjustment for gains included in net income	(3)	0	(19)	0
Net securities gain (loss) activity during the period	(13,020)	(82,223)	14,248	(221,219)
Tax effect	2,734	17,349	(2,992)	46,538
Net of tax amount	(10,286)	(64,874)	11,256	(174,681)
Defined benefit pension plans:
Amortization of net actuarial loss	15	36	30	72
Net gain activity during the period	15	36	30	72
Tax effect	(4)	(9)	(8)	(18)
Net of tax amount	11	27	22	54
Total other comprehensive income (loss), net of tax	(10,275)	(64,847)	11,278	(174,627)
Comprehensive income (loss)	$ 4,336	$ (39,174)	$ 50,167	$ (125,312)