Inventories (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Inventories Net
Total inventories	$ 1,605,280	$ 1,443,284
New vehicle [Member]
Inventories Net
Total inventories	1,068,905	1,004,893
Used vehicle [Member]
Inventories Net
Total inventories	454,800	364,101
Parts accessories and other [Member]
Inventories Net
Total inventories	$ 81,575	$ 74,290