Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net Income	$ 9,260	$ 7,416	$ 27,521	$ 21,255
Other Comprehensive Income, Net of Tax:
Net Unrealized Securities Holding Gains (Losses) Arising During the Period	(897)	9	(4,017)	465
Reclassification Adjustments for Securities Gains Included in Net Income	0	6	0	6	[1]
Amortization of Net Retirement Plan Actuarial Loss	60	64	181	245
Accretion of Net Retirement Plan Prior Service Credit	20	(2)	60	(5)
Other Comprehensive Income (Loss)	(817)	65	(3,776)	699
Comprehensive Income	$ 8,443	$ 7,481	$ 23,745	$ 21,954

[1] All amounts are net of tax.