- Financial Information for Polaris Acceptance Reflecting Effects of Securitization Facility (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Polaris Acceptance
Schedule of Investments [Line Items]
Revenues	$ 72,093	$ 61,645	$ 66,414
Interest and operating expenses	11,832	7,590	6,182
Net income	60,261	54,055	$ 60,232
Finance receivables, net	573,669	518,199
Other assets	102	96
Total Assets	573,771	518,295
Notes payable/(receivable)	(386,438)	(337,050)
Other liabilities	3,215	3,717
Partners' capital	184,118	177,528
Total Liabilities and Partners' Capital	$ 573,771	$ 518,295
Maximum
Schedule of Investments [Line Items]
Aggregate repurchase obligation	15.00%