New Accounting Standards New Accounting Standards (Impact of adoption of ASU 2014-09) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2018	Jun. 25, 2017	Jul. 01, 2018	Jun. 25, 2017	Jan. 01, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Motorcycles and Related Products	$ 1,525,121	$ 1,577,135	$ 2,889,068	$ 2,905,846
Motorcycles and Related Products cost of goods sold	993,036	1,004,173	1,883,210	1,858,061
Operating income	323,947	399,287	560,364	688,469
Income before provision for income taxes	319,397	394,433	549,547	679,117
Provision for income taxes	77,059	135,566	132,446	233,881
Net income	242,338	258,867	417,101	445,236
Other current assets	166,362	151,423	166,362	151,423		$ 175,853
Deferred income taxes	67,505	170,358	67,505	170,358		109,073
Accrued liabilities	572,440	533,412	572,440	533,412		529,822
Retained earnings	1,906,015	$ 1,654,457	1,906,015	$ 1,654,457		$ 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	1,500,384		2,868,368
Motorcycles and Related Products cost of goods sold	974,385		1,864,623
Operating income	317,861		558,251
Income before provision for income taxes	313,311		547,434
Provision for income taxes	75,584		131,934
Net income	237,727		415,500
Other current assets	201,405		201,405
Deferred income taxes	69,353		69,353
Accrued liabilities	616,956		616,956
Retained earnings	1,898,390		1,898,390
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	24,737		20,700
Motorcycles and Related Products cost of goods sold	18,651		18,587
Operating income	6,086		2,113
Income before provision for income taxes	6,086		2,113
Provision for income taxes	1,475		512
Net income	4,611		1,601
Other current assets	(35,043)		(35,043)
Deferred income taxes	(1,848)		(1,848)
Accrued liabilities	(44,516)		(44,516)
Retained earnings	$ 7,625		$ 7,625		$ 6,000