Note 2 - Discontinued Operations - Results of Discontinued Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jul. 08, 2020
Current assets of discontinued operations	$ 0				$ 86,620				$ 0	$ 86,620
Noncurrent assets from discontinued operations	9,535				0				9,535	0
Current liabilities of discontinued operations	816				6,245				816	6,245
Revenue	225,229	$ 210,830	$ 191,689	$ 210,813	230,555	$ 220,459	$ 217,040	$ 217,333	838,561	885,387	$ 880,417
(Loss) income from continuing operations	$ 11,615	$ 6,052	$ (30,504)	$ (4,087)	$ 258	$ (4,042)	$ 5,245	$ 3,758	$ (14,120)	$ 5,219	$ 40,860
(Loss) income per basic share from continuing operations (in dollars per share)	$ 0.43	$ 0.28	$ (1.36)	$ (0.17)	$ 0.01	$ (0.22)	$ 0.28	$ 0.20	$ (0.81)	$ 0.28	$ 2.23
(Loss) income per diluted share from continuing operations (in dollars per share)	$ 0.43	$ 0.27	$ (1.36)	$ (0.17)	$ 0.01	$ (0.22)	$ 0.28	$ 0.20	$ (0.81)	$ 0.28	$ 2.21
Transport Financial Services [Member]
Discontinued Operation, Tax Effect of Discontinued Operation, Total									$ 9,500	$ 1,100	$ 600
Discontinued Operations, Held-for-sale [Member] | Transport Financial Services [Member]
Total revenue									5,397	9,140	5,038
Operating expenses									1,149	1,876	1,467
Gain on disposal									(3,720)	0	0
Loss contingency									44,151	0	0
Operating (loss) income									(36,183)	7,264	3,571
Interest expense									1,950	2,892	1,363
(Loss) income before income taxes									(38,133)	4,372	2,208
Discontinued Operation, Tax Effect of Discontinued Operation, Total									(9,535)	1,114	565
Net (loss) income from discontinued operations, net of tax									(28,598)	3,258	1,643
Disposal Group, Including Discontinued Operation, Accounts, Notes and Loans Receivable, Net	$ 0				$ 86,620				0	86,620		$ 103,300
Current assets of discontinued operations	0				86,620				0	86,620
Noncurrent deferred tax asset	9,535				0				9,535	0
Noncurrent assets from discontinued operations	9,535				0				9,535	0
Total assets from discontinued operations	9,535				86,620				9,535	86,620
Accounts payable	816				6,245				816	6,245
Current liabilities of discontinued operations	816				6,245				816	6,245
Disposal Group, Including Discontinued Operation, Contingent Liabilities	44,151				0				44,151	0
Total liabilities	$ 44,967				$ 6,245				44,967	6,245
Discontinued Operations, Held-for-sale [Member] | Transport Financial Services [Member] | Pro Forma [Member]
Revenue									838,561	885,387	880,417
(Loss) income from continuing operations									$ (14,120)	$ 5,219	$ 40,860
(Loss) income per basic share from continuing operations (in dollars per share)									$ (0.81)	$ 0.28	$ 2.23
(Loss) income per diluted share from continuing operations (in dollars per share)									$ (0.81)	$ 0.28	$ 2.21