Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance			$ (10,317)				$ (10,317)
Investment securities (gains), net	$ 0			$ 0			(8)	$ (437)
HTM investment securities, net, at amortized cost	(2,888)			(172)			(7,269)	(1,335)
Personnel (expense)	(118,243)			(107,880)			(335,720)	(318,900)
Net other comprehensive (loss) during period	(72,603)	$ (45,764)	(126,708)	(13,702)	$ 7,082	$ (16,811)	(245,074)	(23,431)
Ending Balance	(255,391)						(255,391)
AFS Investment Securities
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(177,726)		(5,266)	30,076		41,325	(5,266)	41,325
Other comprehensive (loss) before reclassifications	(100,092)			(19,827)			(268,413)	(35,829)
Unrealized (losses) on AFS securities transferred to HTM securities							(67,604)
Investment securities (gains), net							(12)	16
HTM investment securities, net, at amortized cost	2,888			172			7,269	1,335
Personnel (expense)	0			0			0	0
Other expense	0			0			0	0
Income tax (expense) benefit	24,810			4,975			83,906	8,548
Net other comprehensive (loss) during period	(72,394)			(14,681)			(244,854)	(25,930)
Ending Balance	(250,120)	(177,726)		15,395	30,076		(250,120)	15,395
Defined Benefit Pension and Postretirement Obligations
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(5,062)		(5,051)	(27,187)		(28,707)	(5,051)	(28,707)
Other comprehensive (loss) before reclassifications	0			0			0	0
Unrealized (losses) on AFS securities transferred to HTM securities							0
Investment securities (gains), net							0	0
HTM investment securities, net, at amortized cost	0			0			0	0
Personnel (expense)	(82)			(37)			(244)	(111)
Other expense	347			1,346			494	3,446
Income tax (expense) benefit	(474)			(330)			(470)	(836)
Net other comprehensive (loss) during period	(209)			979			(221)	2,498
Ending Balance	(5,272)	(5,062)		(26,209)	(27,187)		(5,272)	(26,209)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(182,788)		(10,317)	2,889		12,618	(10,317)	12,618
Other comprehensive (loss) before reclassifications	(100,092)			(19,827)			(268,413)	(35,829)
Unrealized (losses) on AFS securities transferred to HTM securities							(67,604)
Investment securities (gains), net							(12)	16
HTM investment securities, net, at amortized cost	2,888			172			7,269	1,335
Personnel (expense)	(82)			(37)			(244)	(111)
Other expense	347			1,346			494	3,446
Income tax (expense) benefit	24,336			4,644			83,436	7,712
Net other comprehensive (loss) during period	(72,603)	(45,764)	$ (126,708)	(13,702)	7,082	$ (16,811)	(245,074)	(23,431)
Ending Balance	$ (255,391)	$ (182,788)		$ (10,813)	$ 2,889		$ (255,391)	$ (10,813)