Quarterly report pursuant to Section 13 or 15(d)

Finance Receivables - Original Product - Schedule of Finance Receivables for Original Product (Detail)

v3.19.1
Finance Receivables - Original Product - Schedule of Finance Receivables for Original Product (Detail) - Original Product [Member]
3 Months Ended 12 Months Ended
Mar. 31, 2019
USD ($)
Unit
Dec. 31, 2018
USD ($)
Unit
Accounts Notes And Loans Receivable [Line Items]    
Finance receivables outstanding $ 503,000 $ 550,000
Reserve for credit losses (118,000) (125,000)
Finance receivables, net $ 385,000 $ 425,000
Number of active units with delinquent assessments | Unit 770 826
Amount of outstanding interest and late fees on active units $ 10,685,000 $ 11,268,000
Funded During The Current Year [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Finance receivables outstanding 30,000 79,000
1-2 Years Outstanding [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Finance receivables outstanding 55,000 35,000
2-3 Years Outstanding [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Finance receivables outstanding 30,000 18,000
3-4 Years Outstanding [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Finance receivables outstanding 13,000 7,000
Greater Than 4 Years Outstanding [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Finance receivables outstanding $ 375,000 $ 411,000