Fair Value Measurements (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	Sep. 25, 2017
Liabilities, Fair Value Disclosure [Abstract]
Warrant liability	$ 72,667	$ 103,474
Fair Value, Recurring [Member]
Assets, Fair Value Disclosure [Abstract]
Cash equivalents - money market	25,041	20,389
Total Assets	25,041	20,389
Liabilities, Fair Value Disclosure [Abstract]
Interest rate swap		(13,414)
Warrant liability	(72,667)	(103,474)
Total Liabilities	(79,092)	(116,888)
Carrying value, debt	1,369,200	1,479,100
Fair Value, Recurring [Member] | Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Cash equivalents - money market	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, Recurring [Member] | Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Cash equivalents - money market	25,041	20,389
Convertible note hedge fair value			$ 56,100
Total Assets	25,041	20,389
Liabilities, Fair Value Disclosure [Abstract]
Interest rate swap	(6,425)	(13,414)
Warrant liability	0	(9,058)
Total Liabilities	(6,425)	(22,472)
Difference between fair value and carrying value, debt	49,000	70,800
Fair Value, Recurring [Member] | Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Cash equivalents - money market	0	0
Total Assets	0	0
Liabilities, Fair Value Disclosure [Abstract]
Interest rate swap	0	0
Warrant liability	(72,667)	(94,416)
Total Liabilities	(72,667)	$ (94,416)
Fair Value, Recurring [Member] | Total [Member]
Liabilities, Fair Value Disclosure [Abstract]
Interest rate swap	(6,425)
Amazon Warrant C [Member] [Member]
Liabilities, Fair Value Disclosure [Abstract]
Warrant liability	$ (72,700)