Detail of Certain Balance Sheet Accounts (Inventories) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Summary of inventories
New Vehicles Inventory, Gross	$ 1,258,485	$ 1,262,797
Used Vehicles Inventory, Gross	316,070	275,508
Rental Vehicles Inventory, Gross	142,626	134,509
Parts, Accessories and Other Inventory, Gross	74,964	72,917
Inventory, Gross	1,792,145	1,745,731
Lower of cost or market reserves	8,031	7,980
Inventories, net	$ 1,784,114	$ 1,737,751