Note 5 - Property and Equipment (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Note 5 - Property and Equipment (Details) [Line Items]
Depreciation	$ 49,000,000	$ 44,200,000	$ 47,800,000
Gain (Loss) on Disposition of Property Plant Equipment	33,000	(81,000)	(198,000)
Capital Leased Assets, Gross	33,800,000	29,400,000
Capital Leases, Lessee Balance Sheet, Assets by Major Class, Accumulated Depreciation	10,600,000	7,600,000
Capital Leases, Income Statement, Amortization Expense	3,000,000	2,200,000	2,100,000
Revenue Equipment [Member] | Maximum [Member]
Note 5 - Property and Equipment (Details) [Line Items]
Capital Leases of Lessee, Term of Contract	84 months
Revenue Equipment [Member] | Minimum [Member]
Note 5 - Property and Equipment (Details) [Line Items]
Capital Leases of Lessee, Term of Contract	60 months
Net in Depreciation and Amortization Expense [Member]
Note 5 - Property and Equipment (Details) [Line Items]
Gain (Loss) on Disposition of Property Plant Equipment	$ 2,700,000	$ 800,000	$ 4,900,000