New Accounting Standards New Accounting Standards (Impact of adoption of ASU 2014-09) (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 01, 2018	Mar. 26, 2017	Jan. 01, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Motorcycles and Related Products	$ 1,363,947	$ 1,328,711
Motorcycles and Related Products cost of goods sold	890,174	853,888
Operating income	236,417	289,182
Income before provision for income taxes	230,150	284,684
Provision for income taxes	55,387	98,315
Net income	174,763	186,369
Other current assets	150,472	142,362		$ 175,853
Deferred income taxes	77,624	165,196		109,073
Accrued liabilities	566,408	547,637		529,822
Retained earnings	1,725,626	$ 1,459,431		$ 1,607,570
Calculated under Revenue Guidance in Effect before Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Motorcycles and Related Products	1,367,984
Motorcycles and Related Products cost of goods sold	890,238
Operating income	240,390
Income before provision for income taxes	234,123
Provision for income taxes	56,350
Net income	177,773
Other current assets	166,864
Deferred income taxes	79,472
Accrued liabilities	587,662
Retained earnings	1,722,612
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Motorcycles and Related Products	(4,037)
Motorcycles and Related Products cost of goods sold	(64)
Operating income	(3,973)
Income before provision for income taxes	(3,973)
Provision for income taxes	(963)
Net income	(3,010)
Other current assets	(16,392)
Deferred income taxes	(1,848)
Accrued liabilities	(21,254)
Retained earnings	$ 3,014		$ 6,000