Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Earnings Per Share [Abstract]
Net income	$ 8,719	$ 6,139	$ 19,376	$ 1,594
Basic-weighted average shares outstanding (in shares)	28,075	27,891	28,059	27,894
Effect of dilutive potential securities (in shares)	771	248	680	192
Diluted- weighted average shares outstanding (in shares)	28,846	28,139	28,739	28,086
Basic (in dollars per share)	$ 0.31	$ 0.22	$ 0.69	$ 0.06
Diluted (in dollars per share)	$ 0.30	$ 0.22	$ 0.67	$ 0.06
Antidilutive securities excluded from computation of earnings per share (in shares)	800	1,400	500	2,000