Condensed Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]
Balance at Dec. 31, 2016	$ 387,098	$ 203	$ (6,632)	$ 213,078	$ 182,190	$ (1,741)
Net income	12,391	0	0	0	12,391	0
Other comprehensive income	567	0	0	0	0	567
Total comprehensive income	12,958	0	0	0	12,391	567
Cash dividends paid on common shares	2,579	0	0	0	2,579	0
Issuance under equity compensation plans, net	(2,151)	1	0	(2,152)	0	0
Share-based Compensation	866	0	0	866	0	0
Shares issued in connection with acquisition	141,729	33	0	141,696	0	0
Reclassification for the adoption of ASU 2016-09	0	0	0	(5,229)	5,229	0
Balance at Mar. 31, 2017	537,921	237	(6,632)	348,259	197,231	(1,174)
Balance at Dec. 31, 2017	548,573	238	(23,268)	350,061	225,360	(3,818)
Net income	20,921	0	0	0	20,921	0
Other comprehensive income	(6,911)	0	0	0	0	(6,911)
Total comprehensive income	14,010	0	0	0	20,921	(6,911)
Cash dividends paid on common shares	2,542	0	0	0	2,542	0
Repurchase of common stock	3,058	0	3,058	0	0	0
Issuance under equity compensation plans, net	(2,686)	1	0	(2,687)	0	0
Share-based Compensation	718	0	0	718	0	0
Reclassification for the adoption of new accounting standards	0	0	0	0	834	(834)
Balance at Mar. 31, 2018	$ 555,015	$ 239	$ (26,326)	$ 348,092	$ 244,573	$ (11,563)