Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement Of Income And Comprehensive Income [Abstract]
NET INCOME		$ 22,711	$ 20,557	$ 8,055
Other comprehensive income (loss):
Net unrealized holding gains (losses) on available for sale securities		5,107	(4,270)	(1,403)
Reclassification adjustment for gains realized in income	[1]	(4)	(73)	(94)
Net unrealized holding gains (losses)		5,103	(4,343)	(1,497)
Income tax effect		(1,786)	1,520	524
Unrealized holding gains (losses), net of reclassification and tax		3,317	(2,823)	(973)
Change in funded status of post-retirement health plan		(55)	(156)	20
Income tax effect		19	55	(7)
Change in funded status of post-retirement health plan, net of tax		(36)	(101)	13
Other comprehensive income (loss), net of tax		3,281	(2,924)	(960)
TOTAL COMPREHENSIVE INCOME		$ 25,992	$ 17,633	$ 7,095

[1] Pre-tax reclassification adjustments relating to available-for-sale securities are reported in security gains and the tax impact is included in income tax expense on the consolidated statements of income.