Summary of Significant Accounting Policies (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) segment	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Pre-tax loss from foreign currency remeasurements		$ 15,100	$ 21,500
Pre-tax gain from foreign currency remeasurements	$ 15,000
Number of reportable segments | segment	2
Allowance for doubtful accounts receivable	$ 4,100	2,700
Repossessed inventory	19,600	19,300
Other inventories	234,900	221,700
Property, Plant and Equipment [Line Items]
Liability for recall campaign	94,200	79,482	74,217	$ 69,250
Research and development expenses	175,200	172,300	161,200
Advertising costs	135,500	137,400	119,800
Total share-based award compensation expense	32,500	32,300	29,400
Total share-based award compensation expense, net of taxes	20,500	20,400	18,500
Net change in restricted cash	$ 8,458	43,495	11,410
Retail
Property, Plant and Equipment [Line Items]
Threshold days past due for write-off of financing receivable (in days)	120 days
Extended Service Contracts
Property, Plant and Equipment [Line Items]
Deferred revenue related to extended service contracts	$ 4,700	4,500
Recall Campaign
Property, Plant and Equipment [Line Items]
Liability for recall campaign	$ 35,300	$ 13,600	$ 10,200
Parts And Accessories And General Merchandise
Property, Plant and Equipment [Line Items]
Standard product warranty, period (in years)	1 year
All Countries, Excluding Japan | Motorcycles
Property, Plant and Equipment [Line Items]
Standard product warranty, period (in years)	2 years
Japan | Motorcycles
Property, Plant and Equipment [Line Items]
Standard product warranty, period (in years)	3 years
Buildings
Property, Plant and Equipment [Line Items]
Useful lives of property, plant and equipment (in years)	30 years
Building Equipment and Land Improvements
Property, Plant and Equipment [Line Items]
Useful lives of property, plant and equipment (in years)	7 years
Machinery and equipment | Minimum
Property, Plant and Equipment [Line Items]
Useful lives of property, plant and equipment (in years)	3 years
Machinery and equipment | Maximum
Property, Plant and Equipment [Line Items]
Useful lives of property, plant and equipment (in years)	10 years
Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Useful lives of property, plant and equipment (in years)	5 years
Software | Minimum
Property, Plant and Equipment [Line Items]
Useful lives of property, plant and equipment (in years)	3 years
Software | Maximum
Property, Plant and Equipment [Line Items]
Useful lives of property, plant and equipment (in years)	7 years