Fair Value Measurements (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	May 10, 2018	Sep. 25, 2017
Liabilities, Fair Value Disclosure [Abstract]
Warrant liability	$ 372,476	$ 203,782
Fair Value, Measurements, Recurring [Member]
Assets, Fair Value Disclosure [Abstract]
Cash equivalents - money market	27,065	17,986
Derivative Asset	1,576	2,971
Total Assets	28,641	20,957
Liabilities, Fair Value Disclosure [Abstract]
Interest rate swap		(1,138)
Warrant liability	(372,476)	(203,782)
Total Liabilities	(375,973)	(204,920)
Carrying value, debt	1,408,100	1,401,300
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Cash equivalents - money market	0	0
Derivative Asset	0	0
Total Assets	0	0
Liabilities, Fair Value Disclosure [Abstract]
Interest rate swap	0	0
Warrant liability	0	0
Total Liabilities	0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Cash equivalents - money market	27,065	17,986
Derivative Asset	1,576	2,971
Convertible note hedge fair value			$ 50,600	$ 56,097
Total Assets	28,641	20,957
Liabilities, Fair Value Disclosure [Abstract]
Interest rate swap	(3,497)	(1,138)
Note conversion obligation fair value			$ 51,300	$ 57,369
Warrant liability	(340,975)	(203,782)
Total Liabilities	(344,472)	(204,920)
Difference between fair value and carrying value, debt	(5,500)	(6,000)
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Cash equivalents - money market	0	0
Derivative Asset	0	0
Total Assets	0	0
Liabilities, Fair Value Disclosure [Abstract]
Interest rate swap	0	0
Warrant liability	(31,501)	0
Total Liabilities	(31,501)	$ 0
Fair Value, Measurements, Recurring [Member] | Total [Member]
Liabilities, Fair Value Disclosure [Abstract]
Interest rate swap	$ (3,497)