Finance Receivables, Credit Quality Information, and Allowance for Credit Losses - Reconciliation of Allowance for Credit Losses (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of period	$ 58,300	$ 48,910
Provision	23,343	19,515
Credit losses	(26,377)	(22,020)
Recoveries	1,134	1,345
Balance at end of period	56,400	47,750
Finance receivables	$ 912,250	$ 804,956	$ 932,243
Allowance as Percentage of Finance Receivables	6.20%	5.90%
Small Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of period	$ 30,759	$ 24,749
Provision	13,954	11,283
Credit losses	(15,488)	(13,375)
Recoveries	568	709
Balance at end of period	29,793	23,366
Finance receivables	$ 421,712	$ 360,470	437,662
Allowance as Percentage of Finance Receivables	7.10%	6.50%
Large Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of period	$ 23,702	$ 17,548
Provision	8,452	6,878
Credit losses	(9,337)	(6,195)
Recoveries	400	358
Balance at end of period	23,217	18,589
Finance receivables	$ 440,707	$ 363,931	437,998
Allowance as Percentage of Finance Receivables	5.30%	5.10%
Automobile Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of period	$ 1,893	$ 4,025
Provision	109	521
Credit losses	(652)	(1,467)
Recoveries	120	237
Balance at end of period	1,470	3,316
Finance receivables	$ 20,511	$ 48,704	26,154
Allowance as Percentage of Finance Receivables	7.20%	6.80%
Retail Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of period	$ 1,946	$ 2,588
Provision	828	833
Credit losses	(900)	(983)
Recoveries	46	41
Balance at end of period	1,920	2,479
Finance receivables	$ 29,320	$ 31,851	$ 30,429
Allowance as Percentage of Finance Receivables	6.50%	7.80%

The allowance for credit losses as a percentage of total finance receivables.

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- Definition

Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

+ References

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- Definition

Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

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- Definition

Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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- Definition

Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

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Amount of expense related to estimated loss from loan and lease transactions.

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