Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Statement of Comprehensive Income [Abstract]
Net Income	$ 8,127	$ 8,734
Other Comprehensive Income, Net of Tax:
Net Unrealized Securities Holding Gains Arising During the Period	4,098	2,080
Net Unrealized Loss on Cash Flow Hedge Agreements	(219)	0
Amortization of Net Retirement Plan Actuarial Loss	27	121
Amortization of Net Retirement Plan Prior Service Cost	39	42
Other Comprehensive Income	3,945	2,243
Comprehensive Income	$ 12,072	$ 10,977