Victory Motorcycles Wind Down - Narrative (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain from sale of cost method investments		$ (3,570,000)
Victory Motorcycles | Disposal Group, Disposed of by Means Other than Sale, Not Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Charges related to the wind down plan	$ 5,063,000	59,792,000
Impact of other wind-down activities	(2,680,000)	(21,184,000)
Victory Motorcycles | Disposal Group, Disposed of by Means Other than Sale, Not Discontinued Operations, Abandonment
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Charges related to the wind down plan	5,063,000	59,792,000
Liability balance	2,697,000	5,645,000	$ 0
Minimum | Victory Motorcycles | Disposal Group, Disposed of by Means Other than Sale, Not Discontinued Operations, Abandonment
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Estimated charges	$ 2,383,000	$ 77,406,000