Victory Motorcycles Wind Down - Liability Balance (Details) - Victory Motorcycles - Disposal Group, Disposed of by Means Other than Sale, Not Discontinued Operations, Abandonment $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Reserves balance as of January 1, 2017	$ 0
Expenses	41,032
Cash payments / scrapped inventory	35,387
Reserves balance as of December 31, 2017	5,645
Contract termination charges
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Reserves balance as of January 1, 2017	0
Expenses	21,632
Cash payments / scrapped inventory	18,445
Reserves balance as of December 31, 2017	3,187
Inventory charges
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Reserves balance as of January 1, 2017	0
Expenses	10,169
Cash payments / scrapped inventory	9,392
Reserves balance as of December 31, 2017	777
Other costs
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Reserves balance as of January 1, 2017	0
Expenses	9,231
Cash payments / scrapped inventory	7,550
Reserves balance as of December 31, 2017	$ 1,681