Consolidated Statement of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Additional Paid-In Capital	Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adoption of ASC 606 (Note 2) | Accounting Standards Update 2014-09	$ (286)					$ (286)
Balance, December 31, 2017, shares (in shares) at Dec. 31, 2017	28,860,961	28,860,961
Balance, December 31, 2017, Treasury stock, shares (in shares) at Dec. 31, 2017	(711,231)		(711,231)
Balance, December 31, 2017, amount at Dec. 31, 2017	$ 231,266	$ 288	$ (6,540)	$ (26)	$ 174,697	62,847
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	$ 334				334
Exercise of stock options (in shares)	146,765	146,765
Exercise of stock options	$ 816	$ 2			814
Cash flow hedge (net of tax)	269			269
Net income	$ 4,101					4,101
Balance, March 31, 2018, shares (in shares) at Mar. 31, 2018	29,007,726
Balance, March 31, 2018, Treasury stock, shares (in shares) at Mar. 31, 2018	(711,231)		(711,231)
Balance, March 31, 2018, amount at Mar. 31, 2018	$ 236,500	$ 290	$ (6,540)	$ 243	$ 175,845	$ 66,662