Long-term Debt - Repurchase of Outstanding Debt (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended		30 Months Ended
	Mar. 19, 2021	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021
Debt Instrument [Line Items]
Cash Paid				$ 125,952	$ 10,595
Non-cash Gain Recognized				4,022	4,779
2023 Notes
Debt Instrument [Line Items]
Principal Amount		$ 6,400	$ 11,981	131,400	17,681	$ 174,000
Carrying Value of Liability		6,337	10,637	129,974	15,374
Cash Paid	$ 120,000	5,952	5,858	125,952	10,595	$ 152,800
Non-cash Gain Recognized		$ 385	$ 4,779	$ 4,022	$ 4,779