Debt Obligations (Details) - USD ($)	1 Months Ended		3 Months Ended
	Apr. 30, 2020	Mar. 31, 2020	Mar. 31, 2020	Mar. 31, 2019	May 11, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Outstanding principal balance		$ 2,374,011,000	$ 2,374,011,000			$ 2,372,521,000
Finance lease, liability		384,000	384,000			443,000
Assumed market debt adjustments, net		1,285,000	1,285,000			1,218,000
Deferred financing costs, net		(16,325,000)	(16,325,000)			(17,204,000)
Total		2,356,401,000	2,356,401,000			2,354,099,000
Gross borrowings		34,000,000	55,000,000	$ 64,000,000
Gross payments			21,000,000	$ 86,000,000
Subsequent Event
Debt Instrument [Line Items]
Line of Credit Facility, Remaining Borrowing Capacity					$ 254,700,000
Gross borrowings	$ 200,000,000
Revolving Credit Facility
Debt Instrument [Line Items]
Outstanding principal balance		34,000,000	$ 34,000,000			0
Line of credit variable rate base			LIBOR
LIne of credit - interest spread			1.40%
Term Loans
Debt Instrument [Line Items]
Outstanding principal balance		$ 1,622,500,000	$ 1,622,500,000			1,652,500,000
Term Loans | Minimum
Debt Instrument [Line Items]
Interest rate		2.01%	2.01%
Term Loans | Maximum
Debt Instrument [Line Items]
Interest rate		4.59%	4.59%
Secured loan facilities | Minimum
Debt Instrument [Line Items]
Interest rate		3.35%	3.35%
Secured loan facilities | Maximum
Debt Instrument [Line Items]
Interest rate		3.52%	3.52%
Secured Portfolio Loan Facilities
Debt Instrument [Line Items]
Outstanding principal balance		$ 395,000,000	$ 395,000,000			395,000,000
Mortgages
Debt Instrument [Line Items]
Outstanding principal balance		322,127,000	322,127,000			324,578,000
Total		$ 324,168,000	$ 324,168,000			$ 326,849,000
Mortgages | Minimum
Debt Instrument [Line Items]
Interest rate		3.45%	3.45%
Mortgages | Maximum
Debt Instrument [Line Items]
Interest rate		7.91%	7.91%