Net Income Per Share (Computation Of Basic And Diluted Net Income Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Numerator for basic and diluted net income per share:
Net income	$ 5,662	$ 5,894	$ 2,853	$ 5,796	$ 6,195	$ 7,598	$ 3,518	$ 5,639	$ 20,205	$ 22,950	$ 18,242
Denominator for basic net income per share:
Weighted-average common shares outstanding (in shares)	36,727	36,605	36,361	35,916	35,936	35,880	35,761	35,555	36,404	35,784	35,145
Basic net income per share (in dollars per share)	$ 0.15	$ 0.16	$ 0.08	$ 0.16	$ 0.17	$ 0.21	$ 0.10	$ 0.16	$ 0.56	$ 0.64	$ 0.52
Denominator for diluted net income per share:
Diluted weighted-average common shares outstanding (in shares)	37,652	37,454	37,195	36,529	36,597	36,516	36,596	36,668	37,210	36,595	36,330
Diluted net income per share (in dollars per share)	$ 0.15	$ 0.16	$ 0.08	$ 0.16	$ 0.17	$ 0.21	$ 0.10	$ 0.15	$ 0.54	$ 0.63	$ 0.50
Stock Options And Restricted Stock Units
Denominator for diluted net income per share:
Dilutive stock options and restricted stock units (in shares)									781	811	1,185
Performance-Based Restricted Stock Units
Denominator for diluted net income per share:
Dilutive stock options and restricted stock units (in shares)									25	0	0
Common stock
Denominator for basic net income per share:
Weighted-average common shares outstanding (in shares)									36,404	35,784	35,145