CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 26,951	$ 29,306	$ 77,352	$ 84,714
Securities AFS and transferred securities:
Change in unrealized holding gain (loss) on AFS securities during the period	(61,354)	(27,714)	(256,778)	(43,527)
Change in net unrealized loss on securities transferred from AFS to HTM	(6,367)	0	(97,871)	0
Reclassification adjustment for amortization related to AFS and HTM debt securities	1,396	312	2,949	1,118
Reclassification adjustment for net (gain) loss on sale of AFS securities, included in net income	99	(1,381)	3,819	(3,399)
Derivatives:
Change in net unrealized gain (loss) on effective cash flow hedge interest rate swap derivatives	15,226	377	42,819	8,296
Reclassification adjustment of net (gain) loss related to derivatives designated as cash flow hedges	(1,572)	1,617	94	4,784
Pension plans:
Amortization of net actuarial loss, included in net periodic benefit cost	224	316	671	948
Other comprehensive income (loss), before tax	(52,348)	(26,473)	(304,297)	(31,780)
Income tax (expense) benefit related to items of other comprehensive income (loss)	10,993	5,560	63,902	6,674
Other comprehensive income (loss), net of tax	(41,355)	(20,913)	(240,395)	(25,106)
Comprehensive income (loss)	$ (14,404)	$ 8,393	$ (163,043)	$ 59,608