CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Balance at Dec. 31, 2017	$ 13,918	$ 189,077	$ 151,963	$ (1,671)	$ 353,287
Net income			10,550		10,550
Other comprehensive income (loss), net of tax				(3,202)	(3,202)
Impact of adoption of ASU 2016-01			667	(667)
Common cash dividends declared			(834)		(834)
Issuance of shares of common stock as a result of stock purchased under the Employee Stock Purchase Plan	3	100			103
Issuance of shares of common stock as a result of stock options exercised	13	193			206
Stock-based compensation expense		496			496
Restricted stock awards - shares of common stock	7	(7)
Exchange of shares of common stock in connection with payroll taxes for restricted stock and in connection with stock options exercised	(4)	(174)			(178)
Balance at Mar. 31, 2018	13,937	189,685	162,346	(5,540)	360,428
Balance at Dec. 31, 2018	15,718	270,761	192,203	(5,544)	473,138
Net income			12,918		12,918
Other comprehensive income (loss), net of tax				2,344	2,344
Common cash dividends declared			(942)		(942)
Issuance of shares of common stock as a result of stock purchased under the Employee Stock Purchase Plan	4	124			128
Issuance of shares of common stock as a result of stock options exercised	25	263			288
Stock-based compensation expense		722			722
Restricted stock awards - shares of common stock	13	(50)			(37)
Exchange of shares of common stock in connection with payroll taxes for restricted stock and in connection with stock options exercised	(5)	(147)			(152)
Balance at Mar. 31, 2019	$ 15,755	$ 271,673	$ 204,179	$ (3,200)	$ 488,407