Borrowings - Long-Term Borrowings (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Jun. 16, 2017
Line of Credit Facility [Line Items]
Outstanding Principal	$ 931,908
Outstanding Borrowings, net	$ 907,037	$ 1,388,548
Senior Secured Second Lien Notes
Line of Credit Facility [Line Items]
Interest rate			6.75%
Senior Secured Credit Facility
Line of Credit Facility [Line Items]
Interest rate	5.55%	5.13%
Outstanding Principal	$ 400,000	$ 900,000
Discount	(332)	(999)
Deferred Debt Issuance Cost	(6,704)	(18,504)
Outstanding Borrowings, net	$ 392,964	$ 880,497
Senior Secured Credit Facility | Senior Secured Second Lien Notes
Line of Credit Facility [Line Items]
Interest rate	6.75%	6.75%
Outstanding Principal	$ 500,000	$ 500,000
Discount	0	0
Deferred Debt Issuance Cost	(17,811)	(22,961)
Outstanding Borrowings, net	$ 482,189	$ 477,039
SBI Bonds
Line of Credit Facility [Line Items]
Interest rate	5.00%	5.00%
Outstanding Principal	$ 31,908	$ 31,059
Discount	0	0
Deferred Debt Issuance Cost	(24)	(47)
Outstanding Borrowings, net	31,884	31,012
Total Long-term borrowings
Line of Credit Facility [Line Items]
Outstanding Principal	931,908	1,431,059
Discount	(332)	(999)
Deferred Debt Issuance Cost	(24,539)	(41,512)
Outstanding Borrowings, net	$ 907,037	$ 1,388,548