Fair Value Measurements (Details) - Debt Obligations - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt obligations, net	$ 2,319,003	$ 2,354,099
Deferred financing costs, net	(14,466)	(17,204)	$ (17,200)
Debt Instrument, Unamortized Discount (Premium), Net	(1,419)	(1,218)	$ (1,200)
Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	2,337,162	2,393,433
Term Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt obligations, net	1,609,291	1,636,470
Term Loans | Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	1,602,032	1,656,765
Secured Portfolio Loan Facilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt obligations, net	391,011	390,780
Secured Portfolio Loan Facilities | Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	404,971	399,054
Mortgages
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt obligations, net	318,701	326,849
Mortgages | Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	$ 330,159	$ 337,614