Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Consolidated Statements Of Comprehensive Income [Abstract]
Net income	$ 41,573	$ 35,122	$ 30,880
Other comprehensive income (loss):
Change in net unrealized holding gains (losses) on available-for-sale securities	(8,485)	1,631	(17,004)
Change in funded status of pension plan	(4,316)	1,718	1,443
Change in net unrealized loss on derivative instrument	(1,130)
Other comprehensive income (loss) before income taxes	(13,931)	3,349	(15,561)
Income tax expense (benefit)	(4,222)	1,199	(6,433)
Other comprehensive income (loss)	(9,709)	2,150	(9,128)
Comprehensive income	$ 31,864	$ 37,272	$ 21,752