Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Statement of Comprehensive Income [Abstract]
Net income	$ 115,573	$ 87,154	$ 196,742	$ 190,514
AFS investment securities
Net unrealized (losses)	(11,126)	(49,066)	(41,014)	(12,588)
Amortization of net unrealized losses on AFS securities transferred to HTM securities	2,122	2,289	4,182	4,556
Reclassification adjustment for net losses realized in net income	0	0	197	0
Income tax benefit	2,253	11,843	9,138	1,951
Other comprehensive (loss) on AFS securities	(6,751)	(34,934)	(27,498)	(6,081)
Cash flow hedge derivatives
Unrealized Gain (Loss) on Cash Flow Hedging Instruments	(6,787)	(34,147)	(26,248)	(20,384)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax	4,769	3,319	9,592	4,581
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, Tax	(503)	7,867	(2,192)	3,173
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	(2,522)	(22,961)	(18,848)	(12,630)
Defined benefit pension and postretirement obligations
Amortization of prior service cost	(73)	(81)	(144)	(163)
Amortization of actuarial (gain) loss	(7)	(7)	(14)	22
Income tax benefit (expense)	20	(71)	(1,614)	8
Other comprehensive (loss) on pension and postretirement obligations	(60)	(159)	(1,772)	(132)
Total other comprehensive (loss)	(9,333)	(58,054)	(48,117)	(18,843)
Comprehensive income	$ 106,241	$ 29,100	$ 148,625	$ 171,671