U.K. Pension Plan Net Periodic Service Cost (Details) - Freightliner U.K. Pension Plan [Member] £ in Thousands, $ in Thousands	3 Months Ended				12 Months Ended
	Mar. 31, 2017 GBP (£)	Mar. 31, 2017 USD ($)	Mar. 31, 2016 GBP (£)	Mar. 31, 2016 USD ($)	Dec. 31, 2017 GBP (£)	Dec. 31, 2017 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Company contribution % required in shared cost arrangement	60.00%	60.00%
Participant contribution % required in shared cost arrangement	40.00%	40.00%
Service cost	£ 2,988	$ 3,688	£ 2,395	$ 3,427
Interest cost	1,978	2,441	2,227	3,188
Expected return on plan assets	(3,307)	(4,082)	(2,847)	(4,074)
Net periodic benefit cost	1,659	2,047	£ 1,775	$ 2,541
Defined Benefit Plan, Contribution by Employer	£ 1,500	$ 1,900
Scenario, Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Contributions in Current Fiscal Year					£ 5,600	$ 7,000