Note 13 - Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred income tax (assets) liabilities:
Inventory	$ (4,076)	$ (3,637)
Accounts receivable	(231)	(157)
Capital lease obligations	(16,202)	(19,480)
Stock options	(9,026)	(6,899)
Accrued liabilities	(2,481)	(2,533)
State net operating loss carry forward	(2,463)	(2,262)
State tax credit	(312)	(410)
Other	(3,276)	(3,627)
Difference between book and tax basis- Depreciation and amortization	179,325	174,266
Total	141,258	135,261
Deferred Tax Assets, Valuation Allowance, Total	50	50
Net deferred income tax liability	$ 141,308	$ 135,311