Supplemental Consolidating Data (Cash Flows) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2018	Jun. 25, 2017	Jul. 01, 2018	Jun. 25, 2017	Dec. 31, 2017	Dec. 31, 2016
Condensed Cash Flow Statements, Captions [Line Items]
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 1,029,683	$ 1,062,871	$ 1,029,683	$ 1,062,871	$ 746,210	$ 827,131
Cash flows from operating activities:
Net income	242,338	258,867	417,101	445,236
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of intangibles			130,061	107,578
Amortization of deferred loan origination costs			39,396	40,771
Amortization of financing origination fees			4,133	4,079
Pension and Other Postretirement Benefits Cost (Reversal of Cost)			18,954	14,950
Employee benefit plan contributions and payments			(6,422)	(37,307)
Stock compensation expense			19,081	17,497
Net change in wholesale finance receivables related to sales			(171,195)	(271,927)
Provision for credit losses	18,880	26,217	48,932	69,806
Deferred income taxes			1,515	178
Other, net			20,894	(4,163)
Changes in current assets and liabilities:
Accounts receivable, net			(14,882)	(28,239)
Finance receivables - accrued interest and other			4,228	2,067
Inventories			63,957	138,942
Accounts payable and accrued liabilities			161,101	133,120
Derivative instruments			(136)	3,114
Other			(859)	(8,634)
Total adjustments			318,758	181,832
Net cash provided by operating activities			735,859	627,068
Cash flows from investing activities:
Capital expenditures			(69,293)	(69,816)
Origination of finance receivables			(1,999,786)	(1,977,839)
Collections on finance receivables			1,712,884	1,647,799
Other			(11,758)	7,031
Net cash used by investing activities			(367,953)	(392,825)
Cash flows from financing activities:
Proceeds from issuance of medium-term notes			1,144,018	893,668
Repayments of medium-term notes			(877,488)	(400,000)
Repayments of securitization debt			(183,453)	(275,659)
Net increase (decrease) in credit facilities and unsecured commercial paper			56,280	(128,787)
Borrowings of asset-backed commercial paper			120,903	341,625
Repayments of asset-backed commercial paper			(100,660)	(77,732)
Dividends paid			(124,680)	(128,452)
Purchase of common stock for treasury			(111,227)	(243,055)
Issuance of common stock under employee stock option plans			1,965	7,432
Net cash (used by) provided by financing activities			(74,342)	(10,960)
Effect of exchange rate changes on cash, cash equivalents and restricted cash			(10,091)	12,457
Cash, cash equivalents and restricted cash:
Net increase in cash, cash equivalents and restricted cash			283,473	235,740
Reportable Legal Entities | Motorcycles And Related Products Operations
Condensed Cash Flow Statements, Captions [Line Items]
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	627,783	586,892	627,783	586,892	338,186	425,540
Cash flows from operating activities:
Net income	181,579	208,900	419,908	469,345
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of intangibles			127,935	104,157
Amortization of deferred loan origination costs			0	0
Amortization of financing origination fees			331	327
Pension and Other Postretirement Benefits Cost (Reversal of Cost)			18,954	14,950
Employee benefit plan contributions and payments			(6,422)	(37,307)
Stock compensation expense			17,229	15,995
Net change in wholesale finance receivables related to sales			0	0
Provision for credit losses	0	0	0	0
Deferred income taxes			(443)	4,975
Other, net			20,993	(6,422)
Changes in current assets and liabilities:
Accounts receivable, net			(194,831)	(241,569)
Finance receivables - accrued interest and other			0	0
Inventories			63,957	138,942
Accounts payable and accrued liabilities			137,644	112,916
Derivative instruments			(205)	3,106
Other			2,924	(8,683)
Total adjustments			188,066	101,387
Net cash provided by operating activities			607,974	570,732
Cash flows from investing activities:
Capital expenditures			(63,236)	(64,273)
Origination of finance receivables			0	0
Collections on finance receivables			0	0
Other			(11,758)	7,031
Net cash used by investing activities			(74,994)	(57,242)
Cash flows from financing activities:
Proceeds from issuance of medium-term notes			0	0
Repayments of medium-term notes			0	0
Repayments of securitization debt			0	0
Net increase (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			(124,680)	(128,452)
Purchase of common stock for treasury			(111,227)	(243,055)
Issuance of common stock under employee stock option plans			1,965	7,432
Net cash (used by) provided by financing activities			(233,942)	(364,075)
Effect of exchange rate changes on cash, cash equivalents and restricted cash			(9,441)	11,937
Cash, cash equivalents and restricted cash:
Net increase in cash, cash equivalents and restricted cash			289,597	161,352
Reportable Legal Entities | Financial Services Operations
Condensed Cash Flow Statements, Captions [Line Items]
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	401,900	475,979	401,900	475,979	408,024	401,591
Cash flows from operating activities:
Net income	60,926	50,108	107,339	82,015
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of intangibles			2,126	3,421
Amortization of deferred loan origination costs			39,396	40,771
Amortization of financing origination fees			3,802	3,752
Pension and Other Postretirement Benefits Cost (Reversal of Cost)			0	0
Employee benefit plan contributions and payments			0	0
Stock compensation expense			1,852	1,502
Net change in wholesale finance receivables related to sales			0	0
Provision for credit losses	18,880	26,217	48,932	69,806
Deferred income taxes			2,043	(4,586)
Other, net			(245)	2,134
Changes in current assets and liabilities:
Accounts receivable, net			0	0
Finance receivables - accrued interest and other			4,228	2,067
Inventories			0	0
Accounts payable and accrued liabilities			192,410	228,247
Derivative instruments			69	8
Other			1,884	98
Total adjustments			296,497	347,220
Net cash provided by operating activities			403,836	429,235
Cash flows from investing activities:
Capital expenditures			(6,057)	(5,543)
Origination of finance receivables			(4,046,125)	(4,205,868)
Collections on finance receivables			3,593,272	3,608,929
Other			0	0
Net cash used by investing activities			(458,910)	(602,482)
Cash flows from financing activities:
Proceeds from issuance of medium-term notes			1,144,018	893,668
Repayments of medium-term notes			(877,488)	(400,000)
Repayments of securitization debt			(183,453)	(275,659)
Net increase (decrease) in credit facilities and unsecured commercial paper			56,280	(128,787)
Borrowings of asset-backed commercial paper			120,903	341,625
Repayments of asset-backed commercial paper			(100,660)	(77,732)
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			49,600	247,115
Effect of exchange rate changes on cash, cash equivalents and restricted cash			(650)	520
Cash, cash equivalents and restricted cash:
Net increase in cash, cash equivalents and restricted cash			(6,124)	74,388
Eliminations
Condensed Cash Flow Statements, Captions [Line Items]
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	0	0	0	0	$ 0	$ 0
Cash flows from operating activities:
Net income	(167)	(141)	(110,146)	(106,124)
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			(171,195)	(271,927)
Provision for credit losses	$ 0	$ 0	0	0
Deferred income taxes			(85)	(211)
Other, net			146	125
Changes in current assets and liabilities:
Accounts receivable, net			179,949	213,330
Finance receivables - accrued interest and other			0	0
Inventories			0	0
Accounts payable and accrued liabilities			(168,953)	(208,043)
Derivative instruments			0	0
Other			(5,667)	(49)
Total adjustments			(165,805)	(266,775)
Net cash provided by operating activities			(275,951)	(372,899)
Cash flows from investing activities:
Capital expenditures			0	0
Origination of finance receivables			2,046,339	2,228,029
Collections on finance receivables			(1,880,388)	(1,961,130)
Other			0	0
Net cash used by investing activities			165,951	266,899
Cash flows from financing activities:
Proceeds from issuance of medium-term notes			0	0
Repayments of medium-term notes			0	0
Repayments of securitization debt			0	0
Net increase (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