Selected Quarterly Financial Data (Unaudited) - Income Taxes - Tax Benefits (Details) - USD ($) $ in Thousands	3 Months Ended												6 Months Ended			9 Months Ended			12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2013	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Total	$ 16,670	$ 26,048	$ 17,850	$ 20,790	$ 15,266	$ (11,914)	$ (499)	$ 8,101	$ 9,996	$ 7,777	$ 7,345	$ 5,415	$ 38,640	$ 7,602	$ 12,760	$ 64,688	$ (4,312)	$ 20,537	$ 81,358	$ 10,954	$ 30,533
Effective Income Tax Rate Reconciliation, Percent		35.20%	35.40%	35.60%		(49.10%)	(39.90%)	46.00%		38.90%	36.80%	33.30%	35.60%	46.50%	35.20%	35.40%	(54.60%)	36.50%
Unrecognized Tax Benefits	2,285	$ 2,000	$ 2,100	$ 2,000	$ 2,010	$ 1,700	$ 1,300	$ 800	$ 845				$ 2,100	$ 1,300		$ 2,000	$ 1,700		2,285	$ 2,010	$ 845	$ 1,485
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	1,900	1,300	1,300	1,200		900	800	$ 800					1,300	800		1,300	900		1,900
Unrealized Reduction in Goodwill if Realized	$ 400	$ 700	$ 800	$ 800		$ 800	$ 500						$ 800	$ 500		$ 700	$ 800		$ 400