Debt - Narrative (Details) $ in Thousands		3 Months Ended		9 Months Ended
	Jul. 17, 2019	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)
Line of Credit Facility [Line Items]
Loss on extinguishment of debt		$ 0	$ (79)	$ (1,889)	$ (4,536)
Mortgages payable
Line of Credit Facility [Line Items]
Net carrying value of real estate collateralizing the mortgages payable		1,800,000		1,800,000		$ 2,300,000
Repayments of Secured Debt				475,100
Derivative, notional amount		1,100,000		1,100,000		$ 1,300,000
Line of credit
Line of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity		1,400,000		1,400,000
Line of credit | Revolving credit facility
Line of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity		$ 1,000,000		$ 1,000,000
Debt Instrument, Number Of Term Extension Options		2		2
Line of credit | Tranche A-1 Term Loan
Line of Credit Facility [Line Items]
Derivative, notional amount		$ 100,000		$ 100,000
Credit facility, maximum borrowing capacity		200,000		200,000
Line of credit | Tranche A-2 Term Loan
Line of Credit Facility [Line Items]
Derivative, notional amount		137,600		137,600
Credit facility, maximum borrowing capacity		$ 200,000		$ 200,000
London Interbank Offered Rate (LIBOR) [Member] | Line of credit | Tranche A-2 Term Loan
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate, Reduction	40.00%
Debt Instrument, Basis Spread on Variable Rate	1.15%			1.55%
Other Expense [Member]
Line of Credit Facility [Line Items]
Loss on extinguishment of debt				$ 1,900