Other Comprehensive Income (Loss) - Tax Effects of Components in Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Before Tax
Other comprehensive (loss) income	$ (25,608)	$ (63,329)	$ (8,211)	$ (215,728)
Tax Effect
Other comprehensive (loss) income	7,241	18,025	2,969	60,498
After Tax
Total other comprehensive (loss)	(18,367)	(45,304)	(5,242)	(155,230)
Unrealized Gains (Losses) on Debt Securities Available for Sale
Before Tax
Other comprehensive income (loss), before reclassifications	(28,188)	(65,744)	(6,235)	(198,171)
Other comprehensive (loss) income	(28,189)	(65,763)	(17,096)	(197,989)
Tax Effect
Other comprehensive income (loss), before reclassifications	7,971	18,589	2,251	55,528
Other comprehensive (loss) income	7,971	18,595	5,324	55,476
After Tax
Other comprehensive income (loss), before reclassifications	(20,217)	(47,155)	(3,984)	(142,643)
Total other comprehensive (loss)	(20,218)	(47,168)	(11,772)	(142,513)
AOCI, Accumulated Gain (Loss), Debt Securities Available-for-sale, Accretion of Unrealized Gains (Losses), Parent
Before Tax
Reclassification from AOCI, current period	(1)	(19)	(14)	(28)
Tax Effect
Reclassification from AOCI, current period	0	6	5	7
After Tax
Reclassification from AOCI, current period	(1)	(13)	(9)	(21)
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Other Reclassifications, Parent
Before Tax
Reclassification from AOCI, current period			(10,847)	210
Tax Effect
Reclassification from AOCI, current period			3,068	(59)
After Tax
Reclassification from AOCI, current period			(7,779)	151
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent
Before Tax
Other comprehensive income (loss), before reclassifications	2,573	1,639	5,390	7,171
Tax Effect
Other comprehensive income (loss), before reclassifications	(728)	(457)	(1,527)	(2,004)
After Tax
Other comprehensive income (loss), before reclassifications	1,845	1,182	3,863	5,167
Total other comprehensive (loss)	1,845	1,182	3,863	5,167
Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent
Before Tax
Reclassification from AOCI, current period	(14)	(14)	(42)	(42)
Tax Effect
Reclassification from AOCI, current period	4	3	12	11
After Tax
Reclassification from AOCI, current period	(10)	(11)	(30)	(31)
Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent
Before Tax
Reclassification from AOCI, current period	1	(339)	3	(1,017)
Tax Effect
Reclassification from AOCI, current period	0	95	(1)	285
After Tax
Reclassification from AOCI, current period	1	(244)	2	(732)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent
Before Tax
Other comprehensive income (loss), before reclassifications	21	1,148	3,534	(23,851)
Other comprehensive (loss) income	8	795	3,495	(24,910)
Tax Effect
Other comprehensive income (loss), before reclassifications	(6)	(211)	(839)	6,730
Other comprehensive (loss) income	(2)	(113)	(828)	7,026
After Tax
Other comprehensive income (loss), before reclassifications	15	937	2,695	(17,121)
Total other comprehensive (loss)	$ 6	$ 682	$ 2,667	$ (17,884)