Other Comprehensive Income - Schedule of Changes in Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 6,400,802	$ 5,084,066	$ 4,592,120
Other comprehensive income (loss) before reclassifications	17,629	(146,794)	(13,180)
Amounts reclassified from other comprehensive income (loss)	(83)	724	2,966
Other comprehensive income (loss), net	17,546	(146,070)	(10,214)
Ending balance	6,701,391	6,400,802	5,084,066
Total Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(164,002)	(17,932)	(7,718)
Ending balance	(146,456)	(164,002)	(17,932)
Unrealized Gains and Losses on AFS Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(127,818)	9,186	33,290
Other comprehensive income (loss) before reclassifications	12,950	(136,981)	(23,613)
Amounts reclassified from other comprehensive income (loss)	(634)	(23)	(491)
Other comprehensive income (loss), net	12,316	(137,004)	(24,104)
Ending balance	(115,502)	(127,818)	9,186
Unrealized Gains and Losses on Derivatives
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	2,233	(1,332)	(3,906)
Other comprehensive income (loss) before reclassifications	(757)	3,362	127
Amounts reclassified from other comprehensive income (loss)	638	203	2,447
Other comprehensive income (loss), net	(119)	3,565	2,574
Ending balance	2,114	2,233	(1,332)
Defined benefit pension and postretirement benefit plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(38,417)	(25,786)	(37,102)
Other comprehensive income (loss) before reclassifications	5,436	(13,175)	10,306
Amounts reclassified from other comprehensive income (loss)	(87)	544	1,010
Other comprehensive income (loss), net	5,349	(12,631)	11,316
Ending balance	$ (33,068)	$ (38,417)	$ (25,786)