Accumulated Other Comprehensive Income (Loss) - Accumulated Other Comprehensive Income, Changes In (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
AOCI Attributable to Parent, Net of Tax
Beginning balance, net of tax	$ 731,782	$ 894,400	$ 912,172	$ 875,297
Income tax (expense) benefit	10,993	5,560	63,902	6,674
Ending balance, net of tax	707,636	877,866	707,636	877,866
Unrealized Gains (Losses) on Securities
AOCI Attributable to Parent, Net of Tax
Beginning balance, net of tax	(137,792)	102,628	84,716	116,078
Other comprehensive (loss) income before reclassifications	(67,721)	(27,714)	(354,649)	(43,527)
Reclassification adjustments included in net income	1,495	(1,069)	6,768	(2,281)
Income tax (expense) benefit	13,908	6,045	73,055	9,620
Net current-period other comprehensive income (loss), net of tax	(52,318)	(22,738)	(274,826)	(36,188)
Ending balance, net of tax	(190,110)	79,890	(190,110)	79,890
Unrealized Gains (Losses) on Derivatives
AOCI Attributable to Parent, Net of Tax
Beginning balance, net of tax	21,857	(8,334)	(1,257)	(17,091)
Other comprehensive (loss) income before reclassifications	15,226	377	42,819	8,296
Reclassification adjustments included in net income	(1,572)	1,617	94	4,784
Income tax (expense) benefit	(2,868)	(418)	(9,013)	(2,747)
Net current-period other comprehensive income (loss), net of tax	10,786	1,576	33,900	10,333
Ending balance, net of tax	32,643	(6,758)	32,643	(6,758)
Retirement Plans
AOCI Attributable to Parent, Net of Tax
Beginning balance, net of tax	(23,400)	(29,407)	(23,754)	(29,907)
Other comprehensive (loss) income before reclassifications	0	0	0	0
Reclassification adjustments included in net income	224	316	671	948
Income tax (expense) benefit	(47)	(67)	(140)	(199)
Net current-period other comprehensive income (loss), net of tax	177	249	531	749
Ending balance, net of tax	(23,223)	(29,158)	(23,223)	(29,158)
Total
AOCI Attributable to Parent, Net of Tax
Beginning balance, net of tax	(139,335)	64,887	59,705	69,080
Other comprehensive (loss) income before reclassifications	(52,495)	(27,337)	(311,830)	(35,231)
Reclassification adjustments included in net income	147	864	7,533	3,451
Income tax (expense) benefit	10,993	5,560	63,902	6,674
Net current-period other comprehensive income (loss), net of tax	(41,355)	(20,913)	(240,395)	(25,106)
Ending balance, net of tax	$ (180,690)	$ 43,974	$ (180,690)	$ 43,974