Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance		$ (10,317)			$ (10,317)
Investment securities (gains), net	$ (8)		$ (362)		(8)	$ (437)
HTM investment securities, net, at amortized cost	(3,273)		(645)		(4,381)	(1,163)
Personnel expense	(112,666)		(106,994)		(217,477)	(211,020)
Net other comprehensive (loss) during period	(45,764)	(126,708)	7,082	$ (16,811)	(172,472)	(9,729)
Ending Balance	(182,788)				(182,788)
AFS Investment Securities
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(131,968)	(5,266)	23,754	41,325	(5,266)	41,325
Other comprehensive (loss) before reclassifications	(65,038)		7,978		(168,321)	(16,002)
Unrealized (losses) on AFS securities transferred to HTM securities					(67,604)
Investment securities (gains), net	8		(24)		(12)	16
HTM investment securities, net, at amortized cost	3,273		645		4,381	1,163
Personnel expense	0		0		0	0
Other expense	0		0		0	0
Income tax benefit	15,998		(2,277)		59,096	3,574
Net other comprehensive (loss) during period	(45,758)		6,322		(172,460)	(11,249)
Ending Balance	(177,726)	(131,968)	30,076	23,754	(177,726)	30,076
Defined Benefit Pension and Postretirement Obligations
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(5,057)	(5,051)	(27,947)	(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		0	0
HTM investment securities, net, at amortized cost	0		0		0	0
Personnel expense	(81)		(37)		(163)	(74)
Other expense	74		1,050		147	2,100
Income tax benefit	2		(253)		4	(506)
Net other comprehensive (loss) during period	(6)		760		(12)	1,519
Ending Balance	(5,062)	(5,057)	(27,187)	(27,947)	(5,062)	(27,187)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(137,024)	(10,317)	(4,193)	12,618	(10,317)	12,618
Other comprehensive (loss) before reclassifications	(65,038)		7,978		(168,321)	(16,002)
Unrealized (losses) on AFS securities transferred to HTM securities					(67,604)
Investment securities (gains), net	8		(24)		(12)	16
HTM investment securities, net, at amortized cost	3,273		645		4,381	1,163
Personnel expense	(81)		(37)		(163)	(74)
Other expense	74		1,050		147	2,100
Income tax benefit	16,000		(2,530)		59,100	3,068
Net other comprehensive (loss) during period	(45,764)	(126,708)	7,082	(16,811)	(172,472)	(9,729)
Ending Balance	$ (182,788)	$ (137,024)	$ 2,889	$ (4,193)	$ (182,788)	$ 2,889