CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (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	$ 24,893	$ 25,405	$ 50,927	$ 50,401
Securities AFS and transferred securities:
Change in unrealized holding gain (loss) on AFS securities during the period	6,831	(33,523)	19,850	(195,424)
Change in net unrealized loss on securities transferred from AFS to HTM	0	(52,360)	0	(91,504)
Reclassification adjustment for amortization related to AFS and HTM debt securities	1,989	1,310	3,981	1,553
Reclassification adjustment for net (gain) loss on sale of AFS securities, included in net income	3,455	2,177	5,601	3,720
Derivatives:
Change in net unrealized gain (loss) on effective cash flow hedge interest rate swap derivatives	15,876	7,047	8,900	27,593
Reclassification adjustment of net (gain) loss related to derivatives designated as cash flow hedges	(6,054)	344	(11,162)	1,666
Pension plans:
Amortization of net actuarial loss, included in net periodic benefit cost	205	241	378	447
Other comprehensive income (loss), before tax	22,302	(74,764)	27,548	(251,949)
Income tax (expense) benefit related to items of other comprehensive income (loss)	(4,683)	15,700	(5,785)	52,909
Other comprehensive income (loss), net of tax	17,619	(59,064)	21,763	(199,040)
Comprehensive income (loss)	$ 42,512	$ (33,659)	$ 72,690	$ (148,639)