Investments in Partnerships - Mortgage Loan Activity (Details) - Mortgage Loan	9 Months Ended
	Sep. 30, 2020
Debt Instrument [Line Items]
Mortgage loan, repayment start period	2020-08
Mortgage loan, repayment end period	2021-02
Minimum
Debt Instrument [Line Items]
Deferral period, repayment of deferred amounts	4 months
Maximum
Debt Instrument [Line Items]
Deferral period, repayment of deferred amounts	6 months