Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Statement of Comprehensive Income [Abstract]
Net income		$ 60,808	$ 71,897	$ 184,699	$ 186,770
Other comprehensive (loss) income, net of tax
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, after Tax		(7,921)	(42,582)	(2,304)	(128,872)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax		202	(27,144)	4,917	(52,743)
Net change in other comprehensive income for defined benefit postretirement plans	[1]	(92)	121	(275)	363
Total other comprehensive (loss) income		(7,811)	(69,605)	2,338	(181,252)
Total comprehensive income		$ 52,997	$ 2,292	$ 187,037	$ 5,518

[1] The amortization of prior service costs is included in the computation of net periodic pension cost as disclosed in Note 13 - Employee Benefit Plans within the Notes to the Consolidated Financial Statements included in Item 8 of the Company's 2022 Form 10-K.