Note 13 - Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred income tax (assets) liabilities:
Inventory	$ (3,637)	$ (5,074)
Accounts receivable	(157)	(203)
Capital lease obligations	(19,480)	(31,263)
Stock options	(6,899)	(11,655)
Accrued liabilities	(2,533)	(3,610)
State net operating loss carry forward	(2,262)	(1,921)
State tax credit	(410)	(380)
Other	(3,627)	(5,170)
Difference between book and tax basis- Depreciation and amortization	174,266	256,352
Total	135,261	197,076
Deferred Tax Assets, Valuation Allowance	50	255
Net deferred income tax liability	$ 135,311	$ 197,331