Summary of Significant Accounting Policies (Details) $ in Millions	3 Months Ended
	Mar. 31, 2020 USD ($) Entity Property	Mar. 31, 2019 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of third-party joint venture partners (entities) | Entity	5
Number of properties	166
Six joint ventures
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of properties	10
On-campus participating properties
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of properties	6
Student Lease Property
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Lease income | $	$ 231.4	$ 221.7
Commercial Lease Property
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Lease income | $	$ 3.2	$ 3.4