Detail of Certain Balance Sheet Accounts (Accounts and Notes Receivable) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Accounts and notes receivable
Total accounts and notes receivable	$ 161,158	$ 176,260
Less allowance for doubtful accounts	2,616	2,896
Accounts and notes receivable, net	158,542	173,364
Amounts due from manufacturers [Member]
Accounts and notes receivable
Total accounts and notes receivable	87,967	95,754
Parts and service receivables [Member]
Accounts and notes receivable
Total accounts and notes receivable	36,293	35,318
Finance and insurance receivables, net [Member]
Accounts and notes receivable
Total accounts and notes receivable	20,412	24,866
Other [Member]
Accounts and notes receivable
Total accounts and notes receivable	$ 16,486	$ 20,322