Asset-Backed Financing (Narrative) (Detail)	1 Months Ended	3 Months Ended	12 Months Ended
	Jun. 30, 2016 CAD	Jun. 26, 2016 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 14, 2016 USD ($)
Variable Interest Entity [Line Items]
Company issued secured notes, net of discount and issuance costs			$ 5,751,859,000	$ 5,670,818,000
Financial Services interest expense			173,756,000	161,983,000	$ 164,476,000
Servicing and ancillary fees			1,600,000
Secured Debt
Variable Interest Entity [Line Items]
Company issued secured notes, net of discount and issuance costs			945,613,000	1,613,216,000
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Receivables transferred to Special Purpose Entities				1,300,000,000
Variable Interest Entity, Primary Beneficiary | Secured Debt
Variable Interest Entity [Line Items]
Financial Services interest expense			$ 13,100,000	$ 17,200,000
Weighted average interest rate at date of issuance			1.31%	1.04%
Variable Interest Entity, Primary Beneficiary | Secured Debt | Secured Notes Issued January 2015
Variable Interest Entity [Line Items]
Weighted average interest rate at date of issuance			0.89%
Variable Interest Entity, Primary Beneficiary | Secured Debt | Secured Notes Issued January 2015 | Term asset-backed securitizations
Variable Interest Entity [Line Items]
Company issued secured notes				$ 700,000,000
Company issued secured notes, net of discount and issuance costs				697,600,000
Variable Interest Entity, Primary Beneficiary | Secured Debt | Term asset-backed securitizations
Variable Interest Entity [Line Items]
Weighted average interest rate at date of issuance			0.88%
Variable Interest Entity, Primary Beneficiary | Secured Debt | Term asset-backed securitizations | Term asset-backed securitizations
Variable Interest Entity [Line Items]
Company issued secured notes				500,000,000
Company issued secured notes, net of discount and issuance costs				498,100,000
Variable Interest Entity, Primary Beneficiary | Secured Debt | Asset-Backed U.S. Commercial Paper Conduit Facility VIE | Line of Credit
Variable Interest Entity [Line Items]
Financial Services interest expense			$ 1,300,000	1,100,000
Variable Interest Entity, Primary Beneficiary | Secured Debt | Asset-Backed U.S. Commercial Paper Conduit Facility VIE | U.S. Line of Credit
Variable Interest Entity [Line Items]
Line of credit, maximum borrowing capacity						$ 900,000,000
Borrowings outstanding under conduit facility			0	0
Variable Interest Entity, Primary Beneficiary | Secured Debt | Asset-Backed U.S. Commercial Paper Conduit Facility VIE, Facility 1 | U.S. Line of Credit
Variable Interest Entity [Line Items]
Line of credit, maximum borrowing capacity						600,000,000
Variable Interest Entity, Primary Beneficiary | Secured Debt | Asset-Backed U.S. Commercial Paper Conduit Facility VIE, Facility 2 | U.S. Line of Credit
Variable Interest Entity [Line Items]
Line of credit, maximum borrowing capacity						$ 300,000,000
Unconsolidated VIEs
Variable Interest Entity [Line Items]
Principal balance of finance receivable		$ 301,800,000
Gain on sale of finance receivable		9,300,000
Cash proceeds from sale of financial asset		$ 312,600,000
Unpaid principal balance of the retail motorcycle finance receivables			236,700,000
Unconsolidated VIEs | Secured Debt | Asset-backed Canadian commercial paper conduit facility
Variable Interest Entity [Line Items]
Financial Services interest expense			$ 2,700,000	$ 3,000,000
Weighted average interest rate at date of issuance			1.84%	1.80%
Unconsolidated VIEs | Secured Debt | Asset-backed Canadian commercial paper conduit facility | Foreign Line of Credit
Variable Interest Entity [Line Items]
Line of credit, maximum borrowing capacity | CAD	CAD 240,000,000
Debt instrument, term	5 years
Transfers on finance receivables			$ 71,100,000	$ 100,000,000
Amount transferred, face amount			62,400,000	$ 87,500,000
VIE, maximum loss exposure, amount			$ 23,300,000