Fair Value Measurements (Details 2) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Business Acquisition, Contingent Consideration [Line Items]
Additions	$ 36,000	$ 0	$ 274,500	$ 0
Changes in fair value	(2,201)	4,019	5,643	3,220
Payments	0	0	0	(5,000)
Fair Value, Measurements, Recurring
Business Acquisition, Contingent Consideration [Line Items]
Fair value, beginning of period	461,800	275,100	215,500	280,900
Fair value, end of period	$ 495,600	$ 279,100	$ 495,600	$ 279,100