Loans and Finance Receivables, Credit Quality Information and Allowances and Liabilities for Estimated Losses on Loans and Finance Receivables - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Accounts Notes And Loans Receivable [Line Items]
Days for delinquent loans to be charged off	60 days
Active consumer loans owned by third-party lenders	$ 26.7	$ 34.1	$ 25.4
Accrual for losses on consumer loan guaranty obligations	$ 1.2	$ 1.7	$ 0.9
Minimum
Accounts Notes And Loans Receivable [Line Items]
Days for delinquent loans to be charged off	60 days
Delinquent loans expiry period (in days)	1 day
Maximum
Accounts Notes And Loans Receivable [Line Items]
Days for delinquent loans to be charged off	65 days
Delinquent loans expiry period (in days)	64 days