Debt - Convertible Notes Hedge Transactions (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) $ / shares
2017 Convertible Senior Notes [Member]
Debt Instrument [Line Items]
Cost of the hedge transaction(s) | $	$ 50,595
Conversion price (in dollars per share)	$ 31.56
2020 Convertible Senior Notes [Member]
Debt Instrument [Line Items]
Cost of the hedge transaction(s) | $	$ 18,113
Conversion price (in dollars per share)	$ 45.72
2021 Convertible Senior Notes [Member]
Debt Instrument [Line Items]
Cost of the hedge transaction(s) | $	$ 19,545
Conversion price (in dollars per share)	$ 59.39
Hedging of Convertible Debt Instrument [Member] | 2017 Convertible Senior Notes [Member]
Debt Instrument [Line Items]
Conversion price (in dollars per share)	60.00
Hedging of Convertible Debt Instrument [Member] | 2020 Convertible Senior Notes [Member]
Debt Instrument [Line Items]
Conversion price (in dollars per share)	61.55
Hedging of Convertible Debt Instrument [Member] | 2021 Convertible Senior Notes [Member]
Debt Instrument [Line Items]
Conversion price (in dollars per share)	$ 83.14