Debt - Schedule of Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Debt Instrument [Line Items]
Amortization of debt discount and issuance costs	$ 12,982	$ 15,295	$ 35,657	$ 31,045
Capitalization of interest expense	(1,849)	(1,210)	(4,896)	(3,200)
Total interest expense	12,127	14,566	32,689	28,620
Credit Agreement
Debt Instrument [Line Items]
Interest on debt instruments	156	122	372	261
Convertible Debt \| 2025 Notes
Debt Instrument [Line Items]
Interest on debt instruments	359	359	1,077	514
Convertible Debt \| 2027 Notes
Debt Instrument [Line Items]
Interest on debt instruments	$ 479	$ 0	$ 479	$ 0

Increase for accrued, but unpaid interest on the debt instrument for the period.

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Amount of the cost of borrowed funds accounted for as interest expense.

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