Acquisitions - Additional Information (Details) shares in Millions						3 Months Ended		4 Months Ended	6 Months Ended	9 Months Ended
	Oct. 02, 2017 USD ($)	Mar. 21, 2017 USD ($)	Mar. 06, 2017 USD ($)	Feb. 03, 2017 USD ($)	Nov. 30, 2016 USD ($) employee country	Sep. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Mar. 21, 2017 USD ($) shares	Jun. 30, 2017 USD ($)	Sep. 30, 2017 USD ($)	Apr. 05, 2017 USD ($)	Mar. 14, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 14, 2016 USD ($)	Nov. 30, 2016 € / shares	Nov. 17, 2016 USD ($)	Aug. 01, 2016 USD ($)	May 05, 2016 USD ($)
Business Acquisition [Line Items]
Escrow deposits						$ 0				$ 0			$ 744,748,000
Adjustment to preliminary purchase allocation										63,907,000
Goodwill						2,384,758,000				2,384,758,000			2,078,765,000
Acquired indefinite-lived intangible assets						671,800,000				671,800,000
Customer Relationships
Business Acquisition [Line Items]
Acquired indefinite-lived intangible assets						296,700,000				$ 296,700,000
Intangible assets, weighted average useful life (years)										20 years
Noncompete Agreements
Business Acquisition [Line Items]
Intangible assets, weighted average useful life (years)										5 years
Intellectual Property
Business Acquisition [Line Items]
Acquired indefinite-lived intangible assets						5,000,000				$ 5,000,000
Intangible assets, weighted average useful life (years)										20 years
Trade Names
Business Acquisition [Line Items]
Acquired indefinite-lived intangible assets						367,600,000				$ 367,600,000
Faiveley Transport
Business Acquisition [Line Items]
Annual sales of Faiveley					$ 1,200,000,000
Number of employees (more than) | employee					5,700
Number of countries Faiveley operates in | country					24
Purchase price per share (in euros per share) | € / shares															€ 100
Outstanding share capital acquired (as a percent)															51.00%
Percentage of voting interests in Faiveley (as a percent)		100.00%	22.00%	27.00%				100.00%							49.00%
Share conversion ratio															1.1538
Additional share capital acquired (as a percent)			21.00%	27.00%
Cash payment for acquisition		$ 17,500,000	$ 303,200,000	$ 411,800,000				$ 944,300,000
Equity issued in acquisition			$ 300,000	$ 25,200,000				$ 560,200,000
Cumulative share capital acquired (as a percent)		100.00%	99.00%	78.00%				100.00%
Cumulative voting rights acquired (as a percent)		100.00%	98.00%	76.00%				100.00%
Business combination, consideration transferred								$ 1,736,100,000
Equity issued in acquisition (in shares) | shares								6.6
Debt assumed in acquisition								$ 409,900,000
Cash acquired in acquisition								178,300,000
Escrow deposits													$ 744,700,000
Acquisition of noncontrolling interest							$ 8,900,000
Adjustment to current liabilities acquired									$ 51,800,000
Accounts receivable		$ 444,741,000						444,741,000
Current liabilities		805,992,000						805,992,000
Adjustment to other noncurrent assets									29,000,000
Adjustment to preliminary purchase allocation									69,100,000
Accrued share based compensation acquired in acquisition						25,900,000				25,900,000
Revenue reported by acquired entity						294,400,000				851,800,000
Goodwill		$ 1,257,360,000						$ 1,257,360,000
Faiveley Transport | Customer Relationships
Business Acquisition [Line Items]
Adjustment to customer relationships acquired										21,800,000
Faiveley Transport | Restatement Adjustment | Fair Value of Receivables
Business Acquisition [Line Items]
Accounts receivable									2,800,000
Faiveley Transport | Restatement Adjustment | Fair Value of Current Liabilities
Business Acquisition [Line Items]
Current liabilities									36,200,000
Faiveley Transport | Restatement Adjustment | Fair Value of Assets Acquired and Liabilities Assumed
Business Acquisition [Line Items]
Accounts receivable									$ 64,300,000
Current liabilities							$ 64,300,000
Faiveley Transport | Minimum
Business Acquisition [Line Items]
Percentage of business acquisition consideration payable in cash (as a percent)															25.00%
Faiveley Transport | Maximum
Business Acquisition [Line Items]
Percentage of business acquisition consideration payable in cash (as a percent)															45.00%
Acquisitions other than Faiveley
Business Acquisition [Line Items]
Escrow deposits						$ 38,400,000				$ 38,400,000
TTC
Business Acquisition [Line Items]
Purchase price, net of cash acquired											$ 32,511,000
Goodwill											16,309,000
Goodwill tax deduction											$ 16,300,000
ATP
Business Acquisition [Line Items]
Purchase price, net of cash acquired												$ 65,254,000
Goodwill												31,934,000
Goodwill tax deduction												$ 31,900,000.0
Workhorse
Business Acquisition [Line Items]
Purchase price, net of cash acquired														$ 43,827,000
Goodwill														$ 24,373,000
Goodwill deductible for taxes (as a percent)														37.80%
Precision Turbo
Business Acquisition [Line Items]
Purchase price, net of cash acquired																$ 13,826,000
Goodwill																4,019,000
Goodwill tax deduction																$ 4,000,000
Unitrac
Business Acquisition [Line Items]
Purchase price, net of cash acquired																		$ 14,771,000
Goodwill																		2,442,000
Goodwill tax deduction																		$ 2,400,000
AM General Contractor | Subsequent Event
Business Acquisition [Line Items]
Annual sales of Faiveley	$ 25,000,000
Gerken
Business Acquisition [Line Items]
Purchase price, net of cash acquired																	$ 62,847,000
Goodwill																	17,470,000
Goodwill tax deduction																	$ 0