Financial Information for Polaris Acceptance Reflecting Effects of Securitization Facility (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Polaris Acceptance
Schedule of Investments [Line Items]
Revenues	$ 63,548	$ 40,968	$ 13,010
Interest and operating expenses	4,738	3,678	3,044
Net income	58,810	37,290	$ 9,966
Finance receivables, net	472,029	337,088
Other assets	124	122
Total Assets	472,153	337,210
Notes payable/(receivable)	(269,881)	(155,436)
Other liabilities	4,126	3,560
Partners' capital	198,146	178,214
Total Liabilities and Partners' Capital	$ 472,153	$ 337,210
Maximum
Schedule of Investments [Line Items]
Aggregate repurchase obligation	15.00%