Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2022	Mar. 31, 2021
Statement of Comprehensive Income [Abstract]
Net income		$ 53,097	$ 41,711
Other comprehensive income (loss), net of tax
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, after Tax		(62,556)	(7,774)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax		(17,950)	(6,583)
Net change in other comprehensive income for defined benefit postretirement plans	[1]	121	819
Total other comprehensive income (loss)		(80,385)	(13,538)
Total comprehensive income (loss)		$ (27,288)	$ 28,173

[1] The amortization of prior service costs is included in the computation of net periodic pension cost as disclosed in Note 14 "Employee Benefit Plans" within the Notes to the Consolidated Financial Statements included in Item 8 of the Company's 2021 Form 10-K.