Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement of Comprehensive Income [Abstract]
Net income		$ 263,813	$ 120,992	$ 121,167
Other comprehensive (loss) income, net of tax
Net change in fair value of securities available for sale		(118,990)	(22,922)	8,857
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax		(50,767)	(19,139)	16,797
Net change in other comprehensive income for defined benefit postretirement plans	[1]	4,490	3,549	(3,128)
Total other comprehensive (loss) income		(165,267)	(38,512)	22,526
Total comprehensive income		$ 98,546	$ 82,480	$ 143,693

[1] The amortization of prior service costs is included in the computation of net periodic pension costs as disclosed in Note 13 - Employee Benefit Plans within the Notes to the Consolidated Financial Statements in Item 8.