Limited Liability Companies Accounted for Under Equity Method (Parenthetical) (Detail)	Sep. 30, 2019 USD ($)
Brunswick Associates
Schedule Of Equity Method Investments [Line Items]
Third-party term loan	$ 8,100,000
Grayson Properties II | Denison, Texas
Schedule Of Equity Method Investments [Line Items]
Committed investment in equity and debt financing, funded	700,000
Grayson Properties II | Maximum | Denison, Texas
Schedule Of Equity Method Investments [Line Items]
Commitment to investment	17,900,000
Grayson Properties
Schedule Of Equity Method Investments [Line Items]
Third-party term loan	13,700,000
FTX MOB Phase II limited partnership
Schedule Of Equity Method Investments [Line Items]
Third-party term loan	5,000,000.0
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