Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	$ (10,317)
Investment securities (gains), net	0	$ (75)
Net unrealized (losses) on AFS securities transferred to HTM securities	(67,604)	0
Personnel expense	(104,811)	(104,026)
Amortization of Net Unrealized Gain on Available-for-Sale Securities Transfered to Held-to-maturity Securities	(1,108)	(518)
Other comprehensive (loss)	(126,708)	(16,811)
Ending Balance	(137,024)
Investment Securities AFS
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(5,266)	41,325
Other comprehensive (loss) before reclassifications	(103,284)	(23,979)
Net unrealized (losses) on AFS securities transferred to HTM securities, prior to transfer	(67,604)
Investment securities (gains), net	(21)	39
Personnel expense	0	0
Other expense	0	0
Amortization of Net Unrealized Gain on Available-for-Sale Securities Transfered to Held-to-maturity Securities	1,108	518
Income tax benefit	43,098	5,851
Other comprehensive (loss)	(126,702)	(17,571)
Ending Balance	(131,968)	23,754
Defined Benefit Pension and Postretirement Obligations
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(5,051)	(28,707)
Other comprehensive (loss) before reclassifications	0	0
Net unrealized (losses) on AFS securities transferred to HTM securities, prior to transfer	0
Investment securities (gains), net	0	0
Personnel expense	(81)	(37)
Other expense	74	1,050
Amortization of Net Unrealized Gain on Available-for-Sale Securities Transfered to Held-to-maturity Securities	0	0
Income tax benefit	2	(253)
Other comprehensive (loss)	(6)	760
Ending Balance	(5,057)	(27,947)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(10,317)	12,618
Other comprehensive (loss) before reclassifications	(103,284)	(23,979)
Net unrealized (losses) on AFS securities transferred to HTM securities, prior to transfer	(67,604)
Investment securities (gains), net	(21)	39
Personnel expense	(81)	(37)
Other expense	74	1,050
Amortization of Net Unrealized Gain on Available-for-Sale Securities Transfered to Held-to-maturity Securities	1,108	518
Income tax benefit	43,100	5,598
Other comprehensive (loss)	(126,708)	(16,811)
Ending Balance	$ (137,024)	$ (4,193)