Note 13 - Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred income tax (assets) liabilities:
Inventory	$ (5,086)	$ (4,076)
Accounts receivable	(140)	(231)
Finance lease obligations	(21,618)	(16,202)
Finance and operating leases	(12,726)	0
Stock options	(8,749)	(9,026)
Accrued liabilities	(2,989)	(2,481)
State net operating loss carry forward	(2,381)	(2,463)
State tax credit	(196)	(312)
Other	(3,817)	(3,276)
Difference between book and tax basis- Operating lease assets	12,628	0
Difference between book and tax basis- Depreciation and amortization	209,250	179,325
Total	164,176	141,258
Deferred Tax Assets, Valuation Allowance, Total	121	50
Net deferred income tax liability	$ 164,297	$ 141,308