Supplemental Consolidating Data (Cash Flows) (Detail) - USD ($) $ in Thousands	3 Months Ended
	Apr. 01, 2018	Mar. 26, 2017	Dec. 31, 2017	Dec. 31, 2016
Condensed Cash Flow Statements, Captions [Line Items]
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 819,257	$ 929,979	$ 746,210	$ 827,131
Cash flows from operating activities:
Net income	174,763	186,369
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of intangibles	62,473	54,900
Amortization of deferred loan origination costs	20,116	20,078
Amortization of financing origination fees	2,028	2,076
Pension and Other Postretirement Benefits Cost (Reversal of Cost)	9,747	7,475
Employee benefit plan contributions and payments	(5,486)	(29,957)
Stock compensation expense	7,962	6,992
Net change in wholesale finance receivables related to sales	(239,902)	(317,087)
Provision for credit losses	30,052	43,589
Deferred income taxes	3,188	3,989
Other, net	(1,902)	(5,334)
Changes in current assets and liabilities:
Accounts receivable, net	(17,688)	(39,230)
Finance receivables - accrued interest and other	4,758	5,142
Inventories	(21,542)	23,476
Accounts payable and accrued liabilities	148,923	182,928
Derivative instruments	702	3,120
Other	13,402	11,413
Total adjustments	16,831	(26,430)
Net cash provided by operating activities	191,594	159,939
Cash flows from investing activities:
Capital expenditures	(28,436)	(23,967)
Origination of finance receivables	(798,067)	(844,692)
Collections on finance receivables	809,800	781,154
Other	(4,948)	52
Net cash used by investing activities	(21,651)	(87,453)
Cash flows from financing activities:
Proceeds from issuance of medium-term notes	347,553	497,406
Repayments of medium-term notes	0	(400,000)
Repayments of securitization debt	(67,955)	(111,359)
Net decrease in credit facilities and unsecured commercial paper	(234,145)	(101,702)
Borrowings of asset-backed commercial paper	35,504	305,209
Repayments of asset-backed commercial paper	(45,907)	(29,383)
Dividends paid	(62,731)	(64,611)
Purchase of common stock for treasury	(72,968)	(79,753)
Issuance of common stock under employee stock option plans	1,719	7,336
Net cash (used by) provided by financing activities	(98,930)	23,143
Effect of exchange rate changes on cash, cash equivalents and restricted cash	2,034	7,219
Cash, cash equivalents and restricted cash:
Net increase in cash, cash equivalents and restricted cash	73,047	102,848
Reportable Legal Entities | Motorcycles And Related Products Operations
Condensed Cash Flow Statements, Captions [Line Items]
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	403,009	479,439	338,186	425,540
Cash flows from operating activities:
Net income	238,329	260,445
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of intangibles	61,405	53,241
Amortization of deferred loan origination costs	0	0
Amortization of financing origination fees	165	163
Pension and Other Postretirement Benefits Cost (Reversal of Cost)	9,747	7,475
Employee benefit plan contributions and payments	(5,486)	(29,957)
Stock compensation expense	7,072	6,317
Net change in wholesale finance receivables related to sales	0	0
Provision for credit losses	0	0
Deferred income taxes	2,469	6,728
Other, net	(2,081)	(6,728)
Changes in current assets and liabilities:
Accounts receivable, net	(195,123)	(278,803)
Finance receivables - accrued interest and other	0	0
Inventories	(21,542)	23,476
Accounts payable and accrued liabilities	121,833	154,372
Derivative instruments	666	3,120
Other	9,935	5,537
Total adjustments	(10,940)	(55,059)
Net cash provided by operating activities	227,389	205,386
Cash flows from investing activities:
Capital expenditures	(25,746)	(21,686)
Origination of finance receivables	0	0
Collections on finance receivables	0	0
Other	(4,948)	52
Net cash used by investing activities	(30,694)	(21,634)
Cash flows from financing activities:
Proceeds from issuance of medium-term notes	0	0
Repayments of medium-term notes		0
Repayments of securitization debt	0	0
Net decrease in credit facilities and unsecured commercial paper	0	0
Borrowings of asset-backed commercial paper	0	0
Repayments of asset-backed commercial paper	0	0
Dividends paid	(62,731)	(64,611)
Purchase of common stock for treasury	(72,968)	(79,753)
Issuance of common stock under employee stock option plans	1,719	7,336
Net cash (used by) provided by financing activities	(133,980)	(137,028)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	2,108	7,175
Cash, cash equivalents and restricted cash:
Net increase in cash, cash equivalents and restricted cash	64,823	53,899
Reportable Legal Entities | Financial Services Operations
Condensed Cash Flow Statements, Captions [Line Items]
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	416,248	450,540	408,024	401,591
Cash flows from operating activities:
Net income	46,413	31,907
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of intangibles	1,068	1,659
Amortization of deferred loan origination costs	20,116	20,078
Amortization of financing origination fees	1,863	1,913
Pension and Other Postretirement Benefits Cost (Reversal of Cost)	0	0
Employee benefit plan contributions and payments	0	0
Stock compensation expense	890	675
Net change in wholesale finance receivables related to sales	0	0
Provision for credit losses	30,052	43,589
Deferred income taxes	979	(2,230)
Other, net	200	1,411
Changes in current assets and liabilities:
Accounts receivable, net	0	0
Finance receivables - accrued interest and other	4,758	5,142
Inventories	0	0
Accounts payable and accrued liabilities	201,056	263,011
Derivative instruments	36	0
Other	6,269	5,925
Total adjustments	267,287	341,173
Net cash provided by operating activities	313,700	373,080
Cash flows from investing activities:
Capital expenditures	(2,690)	(2,281)
Origination of finance receivables	(1,786,309)	(1,932,599)
Collections on finance receivables	1,558,547	1,556,534
Other	0	0
Net cash used by investing activities	(230,452)	(378,346)
Cash flows from financing activities:
Proceeds from issuance of medium-term notes	347,553	497,406
Repayments of medium-term notes		(400,000)
Repayments of securitization debt	(67,955)	(111,359)
Net decrease in credit facilities and unsecured commercial paper	(234,145)	(101,702)
Borrowings of asset-backed commercial paper	35,504	305,209
Repayments of asset-backed commercial paper	(45,907)	(29,383)
Dividends paid	(110,000)	(106,000)
Purchase of common stock for treasury	0	0
Issuance of common stock under employee stock option plans	0	0
Net cash (used by) provided by financing activities	(74,950)	54,171
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(74)	44
Cash, cash equivalents and restricted cash:
Net increase in cash, cash equivalents and restricted cash	8,224	48,949
Eliminations
Condensed Cash Flow Statements, Captions [Line Items]
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	0	0	$ 0	$ 0
Cash flows from operating activities:
Net income	(109,979)	(105,983)
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of intangibles	0	0
Amortization of deferred loan origination costs	0	0
Amortization of financing origination fees	0	0
Pension and Other Postretirement Benefits Cost (Reversal of Cost)	0	0
Employee benefit plan contributions and payments	0	0
Stock compensation expense	0	0
Net change in wholesale finance receivables related to sales	(239,902)	(317,087)
Provision for credit losses	0	0
Deferred income taxes	(260)	(509)
Other, net	(21)	(17)
Changes in current assets and liabilities:
Accounts receivable, net	177,435	239,573
Finance receivables - accrued interest and other	0	0
Inventories	0	0
Accounts payable and accrued liabilities	(173,966)	(234,455)
Derivative instruments	0	0
Other	(2,802)	(49)
Total adjustments	(239,516)	(312,544)
Net cash provided by operating activities	(349,495)	(418,527)
Cash flows from investing activities:
Capital expenditures	0	0
Origination of finance receivables	988,242	1,087,907
Collections on finance receivables	(748,747)	(775,380)
Other	0	0
Net cash used by investing activities	239,495	312,527
Cash flows from financing activities:
Proceeds from issuance of medium-term notes	0	0
Repayments of medium-term notes		0
Repayments of securitization debt	0	0
Net decrease in credit facilities and unsecured commercial paper	0	0
Borrowings of asset-backed commercial paper	0	0
Repayments of asset-backed commercial paper	0	0
Dividends paid	110,000	106,000
Purchase of common stock for treasury	0	0
Issuance of common stock under employee stock option plans	0	0
Net cash (used by) provided by financing activities	110,000	106,000
Effect of exchange rate changes on cash, cash equivalents and restricted cash	0	0
Cash, cash equivalents and restricted cash:
Net increase in cash, cash equivalents and restricted cash	$ 0	$ 0