Note 6 - Credit Facilities and Long-term Debt (Details Textual)	12 Months Ended
	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Used Vehicle Inventory Financing [Member] | Syndicated Credit Facility [Member] | Reallocation [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 250,000,000
Used Vehicle Inventory Financing [Member] | Syndicated Credit Facility [Member]
Line of Credit Facility, Inventory Collateral, Days in Stock, Maximum	180 days
Line of Credit Facility, Maximum Borrowing Capacity	$ 200,000,000
Used Vehicle Inventory Financing [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument, Basis Spread on Variable Rate	1.50%
Used Vehicle Inventory Financing [Member]
Line of Credit Facility, Interest Rate During Period	1.93%
New Vehicle Floor Plan [Member] | Syndicated Credit Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 1,450,000,000
New Vehicle Floor Plan [Member] | Disposal Group, Held-for-sale, Not Discontinued Operations [Member]
Disposal Group, Including Discontinued Operation, Liabilities	$ 4,900,000
New Vehicle Floor Plan [Member]
Reserve Commitment Percent	95.00%
Maximum Reserve Amount if Reserve is Required	$ 15,000,000
Debt Instrument, Basis Spread on Variable Rate	1.25%
Line of Credit Facility, Interest Rate During Period	1.68%
Revolving Credit Facility [Member] | Syndicated Credit Facility [Member] | Reallocation [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 300,000,000
Revolving Credit Facility [Member] | Syndicated Credit Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 200,000,000
Revolving Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member]
Debt Instrument, Basis Spread on Variable Rate	1.25%
Revolving Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member] | Maximum [Member]
Debt Instrument, Basis Spread on Variable Rate	2.50%
Revolving Credit Facility [Member]
Line of Credit Facility, Interest Rate During Period	2.18%
Syndicated Credit Facility [Member] | Scenario Subject to Lender Approval [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 2,100,000,000
Syndicated Credit Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 1,850,000,000
Number of Financial Institutions	18
Number of Manufacturer Affiliated Finance Companies	8
Floor Plan Notes Payable [Member] | Maximum [Member]
Debt Instrument, Interest Rate, Stated Percentage	3.00%
Minimum [Member] | Mortgages [Member]
Debt Instrument, Interest Rate, Stated Percentage	1.80%
Minimum [Member] | Other 1 [Member]
Debt Instrument, Interest Rate, Stated Percentage	2.20%
Maximum [Member] | Mortgages [Member]
Debt Instrument, Interest Rate, Stated Percentage	5.00%
Maximum [Member] | Other 1 [Member]
Debt Instrument, Interest Rate, Stated Percentage	6.50%
Mortgages [Member]
Percent of Total Mortgage Debt that is Fixed	70.00%
Other 1 [Member]
Long-term Debt	$ 25,200,000
Principal Reduction Accounts Outstanding Amount	$ 0
Disposal Group, Including Discontinued Operation, Liabilities		$ 4,892,000
Number of Financial Institutions	18
Number of Manufacturer Affiliated Finance Companies	8
Principal Reduction Accounts Maximum Deposit Amount	$ 50,000,000
Floor Plan Notes Payable	48,083,000	$ 41,047,000	[1]
Long-term Debt	$ 413,108,000

[1] At December 31, 2014, we had an additional $4.9 million of floor plan notes payable outstanding on our new vehicle floor plan commitment recorded as liability related to assets held for sale.