Consolidated Statement of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net Income	$ 37,475	$ 36,279	$ 29,326
Other Comprehensive Income (Loss), Net of Tax:
Unrealized Net Securities Holding Gains (Losses) Arising During the Year	4,162	(2,116)	(940)
Reclassification Adjustment for Net Securities Losses Included in Net Income	0	0	337
Net Retirement Plan Gain (Loss)	2,614	(2,833)	214
Net Retirement Plan Prior Service Cost	0	(338)	0
Amortization of Net Retirement Plan Actuarial Loss	510	242	362
Amortization of Net Retirement Plan Actuarial Loss	167	80	(8)
Other Comprehensive Income (Loss)	7,453	(4,965)	(35)
Comprehensive Income	$ 44,928	$ 31,314	$ 29,291