Derivative Financial Instruments - Embedded Derivatives (Additional Information) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Sep. 30, 2016	Sep. 10, 2016	Jan. 29, 2016	Dec. 15, 2015
Debt Instrument [Line Items]
Interest rate percentage	6.00%
Gain (loss) on embedded derivative	$ (2,200,000)	$ 200,000	$ (300,000)
Embedded derivative liability	$ 6,200,000	4,000,000	4,200,000
6% Convertible Promissory Notes | Convertible promissory notes
Debt Instrument [Line Items]
Interest rate percentage	6.00%
Debt face amount				$ 260,000,000	$ 75,000,000	$ 25,000,000	$ 160,000,000
Convertible stock price (in dollars per share)	$ 20.61						$ 11.25
Convertible debt, stock price trigger	75.00%
Gain (loss) on embedded derivative		$ (31,500,000)	$ (18,200,000)
Embedded derivative liability					$ 178,000,000