Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Comprehensive Income [Abstract]
Net Income Available to Common Shareholders	$ 88,080	$ 89,595	$ 89,352
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax, Portion Attributable to Parent [Abstract]
Unrealized (loss) gain on available-for-sale securities arising during period	(24,857)	31,157	27,115
Reclassification adjustment for net gains	(312)	(62)	(69)
OCI, Debt Securities, Available-for-Sale, Transfer from Held-to-Maturity, Gain (Loss), before Adjustment and Tax	0	1,562	0
Other comprehensive (loss) income related to available-for-sale securities	(25,169)	32,657	27,046
Other Comprehensive (Income) Loss, Defined Benefit Plan, before Tax, after Reclassification Adjustment, Attributable to Parent [Abstract]
Amortization of actuarial net gains	1,122	1,089	917
Recognition of unrealized gains (losses)	1,726	(352)	(1,447)
Change in underfunded pension liability	2,848	737	(530)
Other comprehensive (loss) income before income taxes	(22,321)	33,394	26,516
Tax effect	5,348	(8,001)	(6,194)
Other comprehensive (loss) income, net of tax	(16,973)	25,393	20,322
Comprehensive income, net of tax	$ 71,107	$ 114,988	$ 109,674