Detail of Certain Balance Sheet Accounts (Accounts and Notes Receivable) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Accounts and notes receivable
Total accounts and notes receivable	$ 151,053	$ 154,971
Less allowance for doubtful accounts	3,943	3,641
Accounts and notes receivable, net	147,110	151,330
Amounts due from manufacturers [Member]
Accounts and notes receivable
Total accounts and notes receivable	88,153	86,062
Parts and service receivables [Member]
Accounts and notes receivable
Total accounts and notes receivable	31,305	35,034
Finance and insurance receivables, net [Member]
Accounts and notes receivable
Total accounts and notes receivable	20,555	20,898
Other [Member]
Accounts and notes receivable
Total accounts and notes receivable	$ 11,040	$ 12,977