Convertible Senior Notes - Note Breakdown (Details) - Convertible Debt [Member] - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Principal	$ 1,322,500	$ 1,322,500
Less: debt discount, net of amortization	(172,368)	(195,966)
Net carrying amount	1,150,132	1,126,534
Equity	$ 230,191	$ 230,191