Summary of Significant Accounting Policies (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($) Joint_Venture Property	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) Joint_Venture Property	Jun. 30, 2019 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of third-party joint venture partners (entities) | Joint_Venture	5		5
Number of properties | Property	166		166
Six joint ventures
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of properties | Property	10		10
On-campus participating properties
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenues	$ 4,101	$ 6,396	$ 14,810	$ 17,844
Rent abatements	$ 1,500
Number of properties | Property	6		6
Student Lease Property
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenues	$ 176,900	194,300	$ 408,300	416,000
Student Lease Property, Resident Hardship Program
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Rent abatements	8,600
Student Lease Property, University Partnerships
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Rent abatements	15,100
Commercial Lease Property
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenues	$ 2,900	$ 3,200	$ 6,100	$ 6,600