Detail of Certain Balance Sheet Accounts (Accounts and Notes Receivable) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Accounts and notes receivable
Total accounts and notes receivable	$ 154,196	$ 160,972
Less allowance for doubtful accounts	2,541	3,204
Accounts and notes receivable, net	151,655	157,768
Amounts due from manufacturers [Member]
Accounts and notes receivable
Total accounts and notes receivable	87,125	93,206
Parts and service receivables [Member]
Accounts and notes receivable
Total accounts and notes receivable	33,651	32,479
Finance and insurance receivables, net [Member]
Accounts and notes receivable
Total accounts and notes receivable	21,381	22,374
Other [Member]
Accounts and notes receivable
Total accounts and notes receivable	$ 12,039	$ 12,913