Note 10 - Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Insurance and claims	$ 10,970	$ 10,269
Net operating loss carryovers	7,759	25,849
Tax credits	11,395	10,942
Leased liability	9,969	15,668
Finance lease obligation	3,848	8,483
State bonus	4,860	6,576
Other	4,917	2,160
Valuation allowance	(242)	(385)
Total deferred tax assets	53,476	79,562
Deferred tax liabilities:
Property and equipment	(78,682)	(97,066)
Investment in partnership	(31,585)	(36,669)
ROU Asset- leases	(9,697)	(15,280)
Other	(4,353)	(7,462)
Sec. 481(a) - finance leases	(588)	(449)
Prepaid expenses	(3,124)	(2,966)
Total deferred tax liabilities	(128,029)	(159,892)
Net deferred tax liability	$ (74,553)	$ (80,330)