Stockholders' Equity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended			12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Stock Repurchase Program
Shares Repurchased Under Board Authorization				1,992,831	2,671,637	2,005,200
Total cost (in dollars)				$ 42,000	$ 48,200	$ 28,200
Average share price (in dollars per share)				$ 21.10	$ 18.03	$ 14.05
Shares repurchased to satisfy minimum statutory withholding tax upon the net settlement of equity awards				418,135	367,367	352,051
Dividend Program
Dividend declared (in dollars per share)	$ 0.07	$ 0.07	$ 0.07
Dividend paid (in dollars per share)	$ 0.07	$ 0.07	$ 0.07
Dividends				$ 7,295
October 2011
Stock Repurchase Program
Amount Authorized by Board (in shares)	4,000,000			4,000,000
Total Shares Purchased				4,000,000
Shares Repurchased Under Board Authorization						1,500,000
May 2013
Stock Repurchase Program
Amount Authorized by Board (in shares)	4,000,000			4,000,000
Total Shares Purchased				4,000,000
Shares Repurchased Under Board Authorization				800,000	2,700,000	500,000
October 2014
Stock Repurchase Program
Amount Authorized by Board (in shares)	4,000,000			4,000,000
Total Shares Purchased				1,200,000
Shares Remaining Under Board Authorization	2,800,000			2,800,000
Shares Repurchased Under Board Authorization				1,200,000