Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Net income		$ 239,502	$ 263,813	$ 120,992
Other comprehensive income (loss), net of tax
Net change in fair value of securities available for sale		32,426	(118,990)	(22,922)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax		16,055	(50,767)	(19,139)
Net change in other comprehensive income for defined benefit postretirement plans	[1]	(224)	4,490	3,549
Total other comprehensive income (loss)		48,257	(165,267)	(38,512)
Total comprehensive income		$ 287,759	$ 98,546	$ 82,480

[1] The amortization of prior service costs is included in the computation of net periodic pension costs as disclosed in Note 12 - Employee Benefit Plans within the Notes to the Consolidated Financial Statements in Item 8.