Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	$ (272,799)
HTM investment securities, net, at amortized cost	(2,267)	$ (1,108)
Unrealized Gain (Loss) on Cash Flow Hedging Instruments	13,763	0
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax	1,262	0
Personnel expense	(116,420)	(104,811)
Net other comprehensive income during period	39,211	(126,708)
Ending Balance	(233,588)
AFS Investment Securities
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(233,192)	(5,266)
Other comprehensive income before reclassifications	36,478	(103,284)
Unrealized gains (losses) on AFS securities transferred to HTM securities		(67,604)
Investment securities losses (gains), net		(21)
HTM investment securities, net, at amortized cost	2,267	1,108
Unrealized Gain (Loss) on Cash Flow Hedging Instruments	0
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax	0
Personnel expense	0	0
Other expense	0	0
Income tax (expense) benefit	(9,892)	43,098
Net other comprehensive income during period	28,853	(126,702)
Ending Balance	(204,339)	(131,968)
Defined Benefit Pension and Postretirement Obligations
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(42,968)	(5,051)
Other comprehensive income before reclassifications	0	0
Unrealized gains (losses) on AFS securities transferred to HTM securities		0
Investment securities losses (gains), net		0
HTM investment securities, net, at amortized cost	0	0
Unrealized Gain (Loss) on Cash Flow Hedging Instruments	0
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax	0
Personnel expense	(81)	(81)
Other expense	30	74
Income tax (expense) benefit	79	2
Net other comprehensive income during period	27	(6)
Ending Balance	(42,940)	(5,057)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(272,799)	(10,317)
Other comprehensive income before reclassifications	36,478	(103,284)
Unrealized gains (losses) on AFS securities transferred to HTM securities		(67,604)
Investment securities losses (gains), net		(21)
HTM investment securities, net, at amortized cost	2,267	1,108
Unrealized Gain (Loss) on Cash Flow Hedging Instruments	13,763
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax	1,262
Personnel expense	(81)	(81)
Other expense	30	74
Income tax (expense) benefit	(14,507)	43,100
Net other comprehensive income during period	39,211	(126,708)
Ending Balance	(233,588)	(137,024)
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	3,360	0
Other comprehensive income before reclassifications	0	0
Unrealized gains (losses) on AFS securities transferred to HTM securities		0
Investment securities losses (gains), net		0
HTM investment securities, net, at amortized cost	0	0
Unrealized Gain (Loss) on Cash Flow Hedging Instruments	13,763
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax	1,262
Personnel expense	0	0
Other expense	0	0
Income tax (expense) benefit	(4,694)	0
Net other comprehensive income during period	10,331	0
Ending Balance	$ 13,691	$ 0