Debt - Schedule of Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Debt Instrument [Line Items]
Amortization of debt discount and issuance costs	$ 13,009	$ 5,832
Capitalization of interest expense	(1,391)	(982)
Total interest expense	12,116	4,850
Credit Agreement
Debt Instrument [Line Items]
Interest on debt instruments	139	0
Convertible Debt \| 2025 Notes
Debt Instrument [Line Items]
Interest on debt instruments	$ 359	$ 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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