v3.21.2

Mortgages - Summary of Mortgages (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Debt instrument, interest rate	5.00%
Mortgages and notes payable	$ 1,597,868	$ 1,547,667
Debt issuance costs, net	(4,658)	(6,435)
Mortgages, net	97,530	107,382
Secured Debt
Debt Instrument [Line Items]
Mortgages and notes payable	97,868	107,667
Debt issuance costs, net	$ (338)	(285)
Wilmington Trust National Association, Due February 28 | Secured Debt
Debt Instrument [Line Items]
Origination Date	2019-04
Maturity Date	2028-02
Debt instrument, interest rate	4.92%
Mortgages and notes payable	$ 47,064	47,945
Wilmington Trust National Association, Due August 25 | Secured Debt
Debt Instrument [Line Items]
Origination Date	2018-06
Maturity Date	2025-08
Debt instrument, interest rate	4.36%
Mortgages and notes payable	$ 19,657	19,947
PNC Bank | Secured Debt
Debt Instrument [Line Items]
Origination Date	2016-10
Maturity Date	2026-11
Debt instrument, interest rate	3.62%
Mortgages and notes payable	$ 17,196	17,498
T2 Durham I, LLC | Secured Debt
Debt Instrument [Line Items]
Origination Date	2021-07
Maturity Date	2024-07
Interest Rate	Greater of Prime + 1.25% or 5.00%
Mortgages and notes payable	$ 7,500	0
T2 Durham I, LLC | Greater of Prime | Secured Debt | Maximum [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	5.00%
T2 Durham I, LLC | Greater of Prime | Secured Debt | Minimum [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	1.25%
Sun Life | Secured Debt
Debt Instrument [Line Items]
Origination Date	2012-03
Maturity Date	2021-10
Debt instrument, interest rate	5.13%
Mortgages and notes payable	$ 0	10,469
Aegon | Secured Debt
Debt Instrument [Line Items]
Origination Date	2012-04
Maturity Date	2023-10
Debt instrument, interest rate	6.38%
Mortgages and notes payable	$ 6,451	7,039
M&T Bank | Secured Debt
Debt Instrument [Line Items]
Origination Date	2017-10
Maturity Date	2021-08
Interest Rate	one - monthLIBOR+3%
Mortgages and notes payable	$ 0	$ 4,769
M&T Bank | 1 Month LIBOR | Secured Debt
Debt Instrument [Line Items]
Basis spread on variable rate	3.00%

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