New Accounting Standards New Accounting Standards (Impact of adoption of ASU 2017-07) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2018	Jun. 25, 2017	Jul. 01, 2018	Jun. 25, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Motorcycles and Related Products cost of goods sold	$ 993,036	$ 1,004,173	$ 1,883,210	$ 1,858,061
Selling, administrative and engineering expense	$ 313,047	291,084	$ 603,233	563,068
Adjustments for New Accounting Pronouncement [Member] | Restatement Adjustment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Motorcycles and Related Products cost of goods sold		2,700		5,300
Selling, administrative and engineering expense		$ (400)		$ (700)