Fair Value Measurements (Details 2) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Business Acquisition, Contingent Consideration [Line Items]
Additions	$ 0	$ 0	$ 274,500	$ 0
Changes in fair value	244	(49,433)	5,887	(46,213)
Payments	(14,500)	(16,500)	(14,500)	(21,500)
Fair Value, Measurements, Recurring
Business Acquisition, Contingent Consideration [Line Items]
Fair value, beginning of period	495,700	279,100	215,500	280,900
Fair value, end of period	$ 481,400	$ 213,200	$ 481,400	$ 213,200