Note 7 - Debt (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Aug. 31, 2010
Line of Credit Facility, Maximum Borrowing Capacity (in Dollars)	$ 85.0
Line of Credit Facility, Maximum Amount Outstanding During Period (in Dollars)	50.0
Debt Instrument, Fee Amount (in Dollars)		0.6
Line of Credit Facility, Amount Outstanding (in Dollars)	6.0
Letters of Credit Outstanding, Amount (in Dollars)	37.2
Line of Credit Facility, Remaining Borrowing Capacity (in Dollars)	38.2
Line of Credit Facility, Covenant Terms	1.0
Debt, Secured with a Cross Default Feature (in Dollars)	123.5
Swing Line Sub Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity (in Dollars)	10.0
Percentage of Aggregate Commitments Allowed On Swing Line Sub Facility	10.00%
Minimum [Member] | Applicable Margin [Member]
Debt Instrument, Basis Spread on Variable Rate	1.25%
Minimum [Member]
Line of Credit Facility, Maximum Borrowing Capacity (in Dollars)	25.0
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage	0.50%
Maximum [Member] | Applicable Margin [Member]
Debt Instrument, Basis Spread on Variable Rate	2.25%
Maximum [Member]
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage	0.75%
Accounts Receivable [Member]
Line of Credit Facility, Borrowing Capacity, Description	85%
Appraised Net Orderly Liquidation Value of Revenue Equipment [Member]
Line Of Credit Facility Borrowing Base Limit Percentage	85.00%
Net Book Value of Revenue Equipment [Member]
Line Of Credit Facility Borrowing Base Limit Percentage	95.00%
Lenders' Aggregate Revolving Commitments under Facility [Member]
Line Of Credit Facility Borrowing Base Limit Percentage	35.00%
Appraised Fair Market Value of Eligible Real Estate [Member]
Line Of Credit Facility Borrowing Base Limit Percentage	65.00%
Availability Block [Member]
Line of Credit Facility, Maximum Borrowing Capacity (in Dollars)	15.0
Base Rate Loans [Member] | Federal Funds Rate [Member]
Debt Instrument, Basis Spread on Variable Rate	0.50%
Base Rate Loans [Member] | LIBOR [Member]
Debt Instrument, Basis Spread on Variable Rate	1.00%
Base Rate Loans [Member]
Line of Credit Facility, Amount Outstanding (in Dollars)	31,000.0
Line of Credit Facility, Interest Rate at Period End	5.00%
LIBOR Loans [Member]
Line of Credit Facility, Amount Outstanding (in Dollars)	6.0
Line of Credit Facility, Interest Rate at Period End	3.00%
Fifth Amendment [Member]
Debt Instrument, Fee Amount (in Dollars)	$ 0.3