Product Warranty and Recall Campaigns (Narrative) (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Jul. 01, 2018	Dec. 31, 2017	Sep. 24, 2017	Jun. 25, 2017	Dec. 31, 2016
Product Information
Liability for recall campaigns	$ 83,924	$ 89,943	$ 94,202	$ 70,807	$ 80,681	$ 79,482
Recall Campaign
Product Information
Liability for recall campaigns	$ 23,900		$ 35,300	$ 6,200
Motorcycles | All Countries, Excluding Japan
Product Information
Standard product warranty, period (in years)	2 years
Motorcycles | Japan
Product Information
Standard product warranty, period (in years)	3 years
Parts and Accessories and General Merchandise
Product Information
Standard product warranty, period (in years)	1 year