Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Earnings Per Share [Abstract]
Net income	$ 18,987	$ 3,299	$ 23,305	$ 10,821
Shares used to compute basic net income per share (in shares)	35,652	35,232	35,587	35,174
Dilutive potential common shares
Stock options (in shares)	39	102	53	104
Unvested restricted stock awards (in shares)	215	170	254	221
Shares used to compute diluted net income per share (in shares)	35,906	35,504	35,894	35,499
Basic net income per share (in dollars per share)	$ 0.53	$ 0.09	$ 0.65	$ 0.31
Diluted net income per share (in dollars per share)	$ 0.53	$ 0.09	$ 0.65	$ 0.30
Dilutive securities included in the calculation (in shares)	1,304	1,005	1,080	992
Anti-dilutive securities excluded from the calculation (in shares)	1,152	1,206	1,148	1,171