Debt - Narrative (Details)		1 Months Ended	12 Months Ended
	Jan. 14, 2022 item	Dec. 31, 2020 USD ($)	Dec. 31, 2021 USD ($) loan	Dec. 31, 2020 USD ($) loan
Mortgages Payable
Mortgages and Line of Credit Facility [Line Items]
Net carrying value of real estate collateralizing the mortgages payable		$ 1,800,000,000	$ 1,800,000,000	$ 1,800,000,000
Mortgages Payable | Interest rate swaps and caps
Mortgages and Line of Credit Facility [Line Items]
Derivative notional amount		1,300,000,000	1,300,000,000	1,300,000,000
Line of credit
Mortgages and Line of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity		1,400,000,000	1,400,000,000	1,400,000,000
Line of credit | Revolving Credit Facility
Mortgages and Line of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity		1,000,000,000.0	1,000,000,000.0	1,000,000,000.0
Letters of Credit Outstanding, Amount		1,500,000	911,000	1,500,000
Line of credit | Tranche A-1 Term Loan
Mortgages and Line of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity		200,000,000.0	200,000,000.0	200,000,000.0
Line of credit | Tranche A-2 Term Loan
Mortgages and Line of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity		200,000,000.0	$ 200,000,000.0	$ 200,000,000.0
Minimum | London Interbank Offered Rate (LIBOR) | Line of credit | Revolving Credit Facility
Mortgages and Line of Credit Facility [Line Items]
Debt Instrument basis spread on variable rate			1.05%
Minimum | London Interbank Offered Rate (LIBOR) | Line of credit | Tranche A-1 Term Loan
Mortgages and Line of Credit Facility [Line Items]
Debt Instrument basis spread on variable rate			1.20%
Minimum | London Interbank Offered Rate (LIBOR) | Line of credit | Tranche A-2 Term Loan
Mortgages and Line of Credit Facility [Line Items]
Debt Instrument basis spread on variable rate			1.15%
Maximum | London Interbank Offered Rate (LIBOR) | Line of credit | Revolving Credit Facility
Mortgages and Line of Credit Facility [Line Items]
Debt Instrument basis spread on variable rate			1.50%
Maximum | London Interbank Offered Rate (LIBOR) | Line of credit | Tranche A-1 Term Loan
Mortgages and Line of Credit Facility [Line Items]
Debt Instrument basis spread on variable rate			1.70%
Maximum | London Interbank Offered Rate (LIBOR) | Line of credit | Tranche A-2 Term Loan
Mortgages and Line of Credit Facility [Line Items]
Debt Instrument basis spread on variable rate			1.70%
Subsequent Event [Member] | Line of credit | Tranche A-1 Term Loan
Mortgages and Line of Credit Facility [Line Items]
Debt Instrument, Number Of Term Extension Options | item	2
Debt Instrument, Extension Period	1 year
Subsequent Event [Member] | Minimum | Secured Overnight Financing Rate [Member] | Line of credit | Tranche A-1 Term Loan
Mortgages and Line of Credit Facility [Line Items]
Debt Instrument basis spread on variable rate	1.05%
Subsequent Event [Member] | Maximum | Secured Overnight Financing Rate [Member] | Line of credit | Tranche A-1 Term Loan
Mortgages and Line of Credit Facility [Line Items]
Debt Instrument basis spread on variable rate	1.65%
4747 Bethesda Avenue, The Bartlett, 1221 Van Street and 220 20th Street | Mortgages Payable
Mortgages and Line of Credit Facility [Line Items]
Number of mortgage loans | loan				4
Principal amount		560,000,000.0		$ 560,000,000.0
RTC West | Mortgages Payable
Mortgages and Line of Credit Facility [Line Items]
Increase in principal balance				$ 20,200,000
West End25 | Mortgages Payable
Mortgages and Line of Credit Facility [Line Items]
Repayments of secured debt		$ 94,700,000
1225 S Clark Street and S Clark Street 1215 | Mortgages Payable
Mortgages and Line of Credit Facility [Line Items]
Number of mortgage loans | loan			2
Principal amount			$ 190,000,000.0