Business Combinations, Pro Forma Information (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Business Acquisition, Pro Forma Information [Abstract]
Revenues	$ 348,204	$ 362,907
Net income	$ 17,076	$ 19,079
Basic net income per share	$ 0.50	$ 0.58
Diluted net income per share	$ 0.50	$ 0.56
Shares used in computing basic net income per share	33,832	33,161
Shares used in computing diluted net income per share	34,241	34,166