Note 4 - Discontinued Operations - Results of Discontinued Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Gain on reversal of contingent loss of discontinued operations	$ (3,412)	$ 0
Noncurrent assets from discontinued operations	1,275		$ 9,535
Current liabilities of discontinued operations	816		816
Total revenue	220,889	210,813
Income (loss) from continuing operations	$ 8,581	$ (3,084)
Income (loss) per basic share from continuing operations (in dollars per share)	$ 0.51	$ (0.17)
Income (loss) per diluted share from continuing operations (in dollars per share)	$ 0.50	$ (0.17)
Transport Financial Services [Member] | Discontinued Operations, Disposed of by Sale [Member]
Total revenue	$ 0	$ 2,739
Operating expenses	0	577
Operating income	0	2,162
Gain on reversal of contingent loss of discontinued operations	(3,412)	0
Interest expense	0	993
Income before income taxes	3,412	1,169
Income tax expense	853	298
Income from discontinued operations, net of tax	2,559	871
Noncurrent deferred tax asset	1,275		9,535
Noncurrent assets from discontinued operations	1,275		9,535
Total assets from discontinued operations	1,275		9,535
Accounts payable	816		816
Current liabilities of discontinued operations	816		816
Long-term contingent loss liability	5,100		44,151
Long-term liabilities of discontinued operations	5,100		44,151
Total liabilities from discontinued operations	5,916		$ 44,967
Transport Financial Services [Member] | Discontinued Operations, Disposed of by Sale [Member] | Pro Forma [Member]
Total revenue	220,889	210,813
Income (loss) from continuing operations	$ 8,581	$ (3,084)
Income (loss) per basic share from continuing operations (in dollars per share)	$ 0.51	$ (0.17)
Income (loss) per diluted share from continuing operations (in dollars per share)	$ 0.50	$ (0.17)