Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Changes in the balances of each component of accumulated other comprehensive income
Accumulated Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Foreign Currency Translation, Net of Tax, Beginning Balance	$ (122,552)	$ (137,613)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax, Portion Attributable to Parent	7,871	4,137
Other Comprehensive Income (Loss), Foreign Currency Translation Gain (Loss) Arising During Period, Tax	0	0
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Tax	0	0
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	7,871	4,137
Accumulated Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Foreign Currency Translation, Net of Tax, Ending Balance	(114,681)	(133,476)
Accumulated Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Interest Rate Swaps, Net of Tax, Beginning Balance	(674)	(9,331)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	10,384	624
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	(2,492)	(234)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax	478	1,361
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	9,405	2,658
Accumulated Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Interest Rate Swaps, Net of Tax, Ending Balance	8,731	(6,673)
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance	(123,226)	(146,944)
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent	18,255	4,761
Other Comprehensive Income (Loss) before Reclassifications, Tax	(2,492)	(234)
Other Comprehensive Income (Loss), Tax	(478)	(1,361)
Other comprehensive income (loss), net of tax	17,276	6,795
Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance	(123,226)	(146,944)	$ (105,950)	$ (140,149)
Floorplan Interest Expense [Member]
Changes in the balances of each component of accumulated other comprehensive income
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, before Tax	0	0
Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, before Tax	1,737	2,948
Other Comprehensive Income (Loss), before Tax	1,737	2,948
Interest Expense [Member]
Changes in the balances of each component of accumulated other comprehensive income
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, before Tax	0	0
Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, before Tax	254	681
Other Comprehensive Income (Loss), before Tax	$ 254	$ 681