Note 5 - Property and Equipment (Details Textual) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Depreciation		$ 71,400	$ 61,900	$ 49,000
Gain (Loss) on Disposition of Property Plant Equipment		207	26	33
Capital Leased Assets, Gross		26,600	19,400
Capital Leases, Lessee Balance Sheet, Assets by Major Class, Accumulated Depreciation		4,200	4,700
Capital Leases, Income Statement, Amortization Expense		$ 1,600	2,000	3,000
Revenue Equipment [Member] | Minimum [Member]
Capital Leases of Lessee, Term of Contract	5 years	5 years
Revenue Equipment [Member] | Maximum [Member]
Capital Leases of Lessee, Term of Contract	7 years	7 years
Net in Depreciation and Amortization Expense [Member]
Gain (Loss) on Disposition of Property Plant Equipment		$ 800	$ 600	$ 2,700