U.K. Pension Plan Net Periodic Service Cost (Details) - Freightliner U.K. Pension Plan [Member] £ in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Dec. 31, 2016 GBP (£)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 GBP (£)	Sep. 30, 2016 USD ($)	Sep. 30, 2015 GBP (£)	Sep. 30, 2015 USD ($)	Sep. 30, 2016 GBP (£)	Sep. 30, 2016 USD ($)	Sep. 30, 2015 GBP (£)	Sep. 30, 2015 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			£ 2,394	$ 3,143	£ 2,767	$ 4,286	£ 7,182	$ 10,006	£ 5,232	$ 8,061
Interest cost			2,227	2,923	2,223	3,444	6,681	9,308	3,977	6,132
Expected return on plan assets			(2,846)	(3,737)	(2,738)	(4,241)	(8,538)	(11,896)	(5,478)	(8,438)
Net periodic benefit cost			£ 1,775	$ 2,329	£ 2,252	$ 3,489	5,325	7,418	£ 3,731	$ 5,755
Company's current year contribution							£ 5,000	$ 6,500
Scenario, Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Contributions in Current Fiscal Year	£ 1,700	$ 2,200