Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Statement of Comprehensive Income [Abstract]
Net income	$ 103,360	$ 74,262
AFS investment securities
Net unrealized gains (losses)	36,478	(103,284)
Unrealized (losses) on AFS securities transferred to HTM securities	0	(67,604)
Amortization of net unrealized losses on AFS securities transferred to HTM securities	2,267	1,108
Reclassification adjustment for net (gains) realized in net income	0	(21)
Income tax benefit (expense)	(9,892)	43,098
Other comprehensive income (loss) on AFS securities	28,853	(126,702)
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
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, Tax	(4,694)	0
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	10,331	0
Defined benefit pension and postretirement obligations
Amortization of prior service cost	(81)	(81)
Amortization of actuarial loss	30	74
Income tax benefit	79	2
Other comprehensive income (loss) on pension and postretirement obligations	27	(6)
Total other comprehensive income (loss)	39,211	(126,708)
Comprehensive income (loss)	$ 142,571	$ (52,445)