Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 33,969	$ 28,194
Unrealized losses on securities available for sale:
Unrealized holding losses arising during the period, pretax	(181,795)	(24,235)
Tax benefit	41,776	5,569
Postretirement Plans:
Amortization of unrecognized net actuarial loss	44	171
Tax benefit	(10)	(40)
Other comprehensive loss	(139,985)	(18,535)
Comprehensive (loss) income	$ (106,016)	$ 9,659

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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