Limited Liability Companies Accounted for Under Equity Method (Parenthetical) (Detail)	Sep. 30, 2020 USD ($)
Brunswick Associates
Schedule Of Equity Method Investments [Line Items]
Third-party term loan	$ 7,900,000
Grayson Properties II
Schedule Of Equity Method Investments [Line Items]
Construction loan	13,100,000
Construction loan outstanding balance	10,400,000
Grayson Properties II | Denison, Texas
Schedule Of Equity Method Investments [Line Items]
Committed investment in equity and debt financing, funded	0
Grayson Properties II | Maximum | Denison, Texas
Schedule Of Equity Method Investments [Line Items]
Commitment to investment	4,800,000
Grayson Properties
Schedule Of Equity Method Investments [Line Items]
Third-party term loan	13,400,000
FTX MOB Phase II limited partnership
Schedule Of Equity Method Investments [Line Items]
Third-party term loan	4,800,000
Committed investment in equity and debt financing, funded	2,100,000
FTX MOB Phase II limited partnership | Maximum
Schedule Of Equity Method Investments [Line Items]
Commitment to investment	$ 2,500,000