Supplemental Consolidating Data (Operations) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 24, 2017	Sep. 30, 2018	Sep. 24, 2017
Revenue:
Motorcycles and Related Products	$ 1,123,945	$ 962,136	$ 4,013,013	$ 3,867,982
Financial Services	191,724	189,059	558,000	550,314
Total revenue	1,315,669	1,151,195	4,571,013	4,418,296
Costs and expenses:
Motorcycles and Related Products cost of goods sold	776,530	687,823	2,659,740	2,545,884
Financial Services interest expense	44,696	46,169	145,089	133,866
Provision for credit losses	23,530	29,253	72,462	99,059
Selling, administrative and engineering expense	306,665	293,538	909,898	856,606
Restructuring expense	14,832	0	74,044	0
Total costs and expenses	1,166,253	1,056,783	3,861,233	3,635,415
Operating income	149,416	94,412	709,780	782,881
Other income (expense), net	644	2,296	1,509	6,887
Investment (loss) income	(1,106)	1,083	2,630	2,539
Interest expense	7,762	7,896	23,180	23,295
Income before provision for income taxes	141,192	89,895	690,739	769,012
Provision for income taxes	27,337	21,686	159,783	255,567
Net income	113,855	68,209	530,956	513,445
Reportable Legal Entities | Motorcycles And Related Products Operations
Revenue:
Motorcycles and Related Products	1,126,977	964,942	4,021,268	3,875,669
Financial Services	0	0	0	0
Total revenue	1,126,977	964,942	4,021,268	3,875,669
Costs and expenses:
Motorcycles and Related Products cost of goods sold	776,530	687,823	2,659,740	2,545,884
Financial Services interest expense	0	0	0	0
Provision for credit losses	0	0	0	0
Selling, administrative and engineering expense	267,316	257,357	798,544	752,134
Restructuring expense	14,832		74,044
Total costs and expenses	1,058,678	945,180	3,532,328	3,298,018
Operating income	68,299	19,762	488,940	577,651
Other income (expense), net	644	2,296	1,509	6,887
Investment (loss) income	(1,106)	91,083	112,630	198,539
Interest expense	7,762	7,896	23,180	23,295
Income before provision for income taxes	60,075	105,245	579,899	759,782
Provision for income taxes	10,613	(6,134)	110,529	179,058
Net income	49,462	111,379	469,370	580,724
Reportable Legal Entities | Financial Services Operations
Revenue:
Motorcycles and Related Products	0	0	0	0
Financial Services	192,188	189,932	559,436	552,201
Total revenue	192,188	189,932	559,436	552,201
Costs and expenses:
Motorcycles and Related Products cost of goods sold	0	0	0	0
Financial Services interest expense	44,696	46,169	145,089	133,866
Provision for credit losses	23,530	29,253	72,462	99,059
Selling, administrative and engineering expense	42,776	39,383	120,830	113,445
Restructuring expense	0		0
Total costs and expenses	111,002	114,805	338,381	346,370
Operating income	81,186	75,127	221,055	205,831
Other income (expense), net	0	0	0	0
Investment (loss) income	0	0	0	0
Interest expense	0	0	0	0
Income before provision for income taxes	81,186	75,127	221,055	205,831
Provision for income taxes	16,724	27,820	49,254	76,509
Net income	64,462	47,307	171,801	129,322
Eliminations
Revenue:
Motorcycles and Related Products	(3,032)	(2,806)	(8,255)	(7,687)
Financial Services	(464)	(873)	(1,436)	(1,887)
Total revenue	(3,496)	(3,679)	(9,691)	(9,574)
Costs and expenses:
Motorcycles and Related Products cost of goods sold	0	0	0	0
Financial Services interest expense	0	0	0	0
Provision for credit losses	0	0	0	0
Selling, administrative and engineering expense	(3,427)	(3,202)	(9,476)	(8,973)
Restructuring expense	0		0
Total costs and expenses	(3,427)	(3,202)	(9,476)	(8,973)
Operating income	(69)	(477)	(215)	(601)
Other income (expense), net	0	0	0	0
Investment (loss) income	0	(90,000)	(110,000)	(196,000)
Interest expense	0	0	0	0
Income before provision for income taxes	(69)	(90,477)	(110,215)	(196,601)
Provision for income taxes	0	0	0	0
Net income	$ (69)	$ (90,477)	$ (110,215)	$ (196,601)