Fair Value Measurements (Details 3) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2013
Business Acquisition, Contingent Consideration [Line Items]
Additions	$ 238,500,000	$ 0
Changes in fair value	7,844,000	(799,000)
Payments	0	(5,000,000)
Fair Value, Measurements, Recurring
Business Acquisition, Contingent Consideration [Line Items]
Fair value, beginning of period			215,500,000	280,900,000
Fair value, end of period	$ 461,800,000	$ 275,100,000	$ 215,500,000	$ 280,900,000