Accumulated Other Comprehensive (Loss) Income (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
AOCI Attributable to Parent, Net of Tax
Balance, beginning	$ 2,843,305	$ 3,177,622
Other comprehensive (loss) income before reclassifications	(32,466)	(523,084)
Total other comprehensive loss, net of tax	(31,575)	(522,507)
Balance, ending	2,874,594	2,772,357
Accumulated Other Compre- hensive (Loss) Income
AOCI Attributable to Parent, Net of Tax
Balance, beginning	(468,792)	27,359
Balance, ending	(500,367)	(495,148)
(Losses) Gains on Available-For-Sale and Transferred Debt Securities
AOCI Attributable to Parent, Net of Tax
Balance, beginning	(474,338)	27,038
Other comprehensive (loss) income before reclassifications	(34,364)	(528,317)
Reclassification adjustments for gains and transfers included in net income	24	(583)
Total other comprehensive loss, net of tax	(30,983)	(527,615)
Balance, ending	(505,321)	(500,577)
(Losses) Gains on Derivatives Used for Cash Flow Hedges
AOCI Attributable to Parent, Net of Tax
Balance, beginning	5,546	321
Other comprehensive (loss) income before reclassifications	1,898	5,233
Reclassification adjustments for gains and transfers included in net income	(2,490)	(125)
Total other comprehensive loss, net of tax	(592)	5,108
Balance, ending	4,954	5,429
Reclassification adjustments for gains and transfers included in net income
AOCI Attributable to Parent, Net of Tax
Reclassification adjustments for gains and transfers included in net income	(2,466)	(708)
Reclassification adjustments for amortization included in net income for transferred securities
AOCI Attributable to Parent, Net of Tax
Reclassification adjustments for gains and transfers included in net income	$ 3,357	$ 1,285