Summary of Significant Accounting Policies - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2021 USD ($) Property State JointVenture shares	Mar. 31, 2020 USD ($) shares	Apr. 23, 2021	Dec. 31, 2020 USD ($) Property	Dec. 31, 2019 shares	Aug. 29, 2018 shares
Summary Of Significant Accounting Policies [Line Items]
Impairment loss on real estate assets	$ 1,700,000	$ 0
Number of real estate assets | Property	1
Number of properties classified | Property	3			1
Real estate held for sale, assets	$ 24,441,000			$ 1,864,000
Real estate held for sale, liabilities	0			$ 0
Impairment loss	0	0
Reduction to rental revenue	200,000	500,000
Reversal of straight line rent	$ 1,000,000.0	$ 0
Revenue performance obligation satisfied over time method used description	Management determined that property and asset management and construction and development management services each represent a series of stand-ready performance obligations satisfied over time with each day of service being a distinct performance obligation.
Number of wholly owned properties acquired | Property	154
Number of entities acquired | JointVenture	25
Number of states in properties located | State	41
Class C Common Shares [Member]
Summary Of Significant Accounting Policies [Line Items]
Common shares, outstanding | shares						0
Class B Common Shares [Member]
Summary Of Significant Accounting Policies [Line Items]
Common shares, outstanding | shares	0	0			1,243,000
Management and Other Fee Income [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage of revenue earned from unconsolidated joint ventures	100.00%
Rent Deferral Agreements [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance to tenant	$ 100,000
Operating Partnership [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage of operating partnership interest held by parent	72.60%
Operating Partnership [Member] | Subsequent Event [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage of operating partnership interest held by parent			76.40%