Financial Instruments and Fair Value Measurements (Details Textual)	1 Months Ended	3 Months Ended			9 Months Ended
	Sep. 30, 2016 USD ($) investment	Sep. 30, 2016 USD ($) investment	Mar. 31, 2016 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($) investment	Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)
Business Acquisition [Line Items]
Impairment charges recorded for earnings					$ 0
Unrealized loss position investment | investment	0	0			0
Net foreign currency exchange (losses) gains, includes gains and losses from derivatives instruments		$ (100,000)		$ 400,000	$ 100,000	$ 400,000
Contingent consideration liability	$ 45,005,000	45,005,000			45,005,000
Contingent Consideration Liabilities [Member]
Business Acquisition [Line Items]
Additions to contingent consideration liabilities with acquisitions					63,400,000
Contingent consideration liability recorded upon acquisition	36,000,000		$ 21,400,000		63,442,000
Contingent consideration liability	65,400,000	65,400,000			65,400,000
Quoted price in active market (Level 1) [Member] | Convertible Notes due 2017 [Member]
Business Acquisition [Line Items]
Debt instrument, fair value disclosure	197,100,000	197,100,000			197,100,000		$ 551,400,000
Quoted price in active market (Level 1) [Member] | Senior Convertible Notes due 2021 [Member]
Business Acquisition [Line Items]
Debt instrument, fair value disclosure	822,000,000	822,000,000			822,000,000
Foreign Exchange Forward [Member]
Business Acquisition [Line Items]
Notional principal amount	$ 14,400,000	$ 14,400,000		$ 16,800,000	$ 14,400,000	$ 16,800,000