Derivative Financial Instruments Foreign Currency Exchange Rate Risk (Details)	3 Months Ended								3 Months Ended		3 Months Ended	0 Months Ended				3 Months Ended						0 Months Ended
	Mar. 31, 2015 USD ($)	Mar. 31, 2014 USD ($)	Mar. 31, 2015 GBP (£)	Mar. 23, 2015 USD ($)	Feb. 25, 2015 British Pound foreign currency forward purchase contract 1 [Member] USD ($)	Feb. 25, 2015 British Pound foreign currency forward purchase contract 1 [Member] GBP (£)	Feb. 25, 2015 British Pound foreign currency forward purchase contract 2 [Member] AUD	Feb. 25, 2015 British Pound foreign currency forward purchase contract 2 [Member] GBP (£)	Mar. 31, 2015 British Pound foreign currency forward purchase contract 3 [Member] USD ($)	Mar. 31, 2015 British Pound foreign currency forward purchase contract 3 [Member] GBP (£)	Mar. 31, 2015 British Pound foreign currency forward purchase contract 4 [Member] USD ($)	May 23, 2014 Cross-currency swap agreements [Member] USD ($)	May 23, 2014 Cross-currency swap agreements [Member] AUD	Dec. 03, 2012 Cross-currency swap agreements [Member] USD ($)	Dec. 03, 2012 Cross-currency swap agreements [Member] AUD	Mar. 31, 2015 Interest Expense [Member] Cross-currency swap agreements [Member] USD ($)	Mar. 31, 2014 Interest Expense [Member] Cross-currency swap agreements [Member] USD ($)	Mar. 31, 2015 Other Nonoperating Income (Expense) [Member] Cross-currency swap agreements [Member] USD ($)	Mar. 31, 2014 Other Nonoperating Income (Expense) [Member] Cross-currency swap agreements [Member] USD ($)	Mar. 31, 2015 Freightliner [Member] USD ($)	Mar. 31, 2015 Freightliner [Member] GBP (£)	Feb. 25, 2015 Scenario, Plan [Member] Freightliner [Member] USD ($)	Feb. 25, 2015 Scenario, Plan [Member] Freightliner [Member] GBP (£)
Derivative [Line Items]
Derivative, Inception Date									Mar. 25, 2015		Mar. 25, 2015
Derivative, Maturity Date									Mar. 25, 2020		Mar. 25, 2020
Derivative, Forward Exchange Rate										1.50	1.51
Gain/(loss) reclassified from accumulated other comprehensive income/(loss) into earnings due to ineffectiveness									$ 0		$ 0
Foreign subsidiaries third-party debt denominated in local currencies	502,300,000
Estimated Payments to Acquire Businesses, Gross																						755,000,000	490,000,000
Foreign Currency Forward Purchase Contracts Not Designated as Hedging Instruments, Gain (Loss), Net	(18,686,000)	0																		(18,700,000)
Cash purchase price																				733,006,000	492,083,000
Notional amount of US to UK intercompany loan	179,200,000		120,000,000
Payments in connection with termination of cross-currency swap													105,000,000
Proceeds in connection with termination of cross-currency swap												108,900,000
Notional amount					475,000,000	307,100,000	163,800,000	84,700,000		60,000,000	60,000,000			109,600,000	105,000,000
Cash received on settlement of forward currency forward purchase contracts				391,800,000
Net expense realized or recognized on cross-currency swap agreement	$ (18,686,000)	$ (378,000)														$ 0	$ (554,000)	$ 0	$ 176,000