Finance Receivables - Special Product (New Neighbor Guaranty program) - Schedule of Delinquent Assessments and Accrued Charges (Detail) - Special Product [Member]	12 Months Ended
	Dec. 31, 2019 USD ($) Unit	Dec. 31, 2018 USD ($) Unit
Accounts Notes And Loans Receivable [Line Items]
Finance receivables, net	$ 129,000	$ 237,000
Delinquent assessments	374,000	707,000
Accrued interest and late fees	$ 235,000	$ 465,000
Number of active units with delinquent assessments | Unit	31	58