Note 15 - Subsequent Events (Details Textual) - USD ($)	Jul. 08, 2020	Jul. 01, 2020	May 08, 2019	Jun. 30, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized (in shares)			750,000
Maximum Number of Shares of Class A Common Stock Awarded to any Participant in the Incentive Plan in any Calendar Year (in shares)				200,000
Maximum Cash Awarded to any Participant in the Incentive Plan in any Calendar Year				$ 2,000,000
Transport Financial Services [Member] | Discontinued Operations, Held-for-sale [Member]
Disposal Group, Including Discontinued Operation, Accounts, Notes and Loans Receivable, Net				98,131,000	$ 86,620,000
Disposal Group, Including Discontinued Operation, Allowance				$ 600,000	$ 408,000
Subsequent Event [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized (in shares)		1,900,000
Fungible Share Reserve Feature, Shares Subject for Each Share Granted (in shares)		1
Fungible Share Reserve Feature, Shares Subject to All Other Awards (in shares)		1.80
Maximum Number of Shares of Class A Common Stock Awarded to any Participant in the Incentive Plan in any Calendar Year (in shares)		500,000
Maximum Cash Awarded to any Participant in the Incentive Plan in any Calendar Year		$ 4,000,000
Subsequent Event [Member] | Transport Financial Services [Member] | Discontinued Operations, Held-for-sale [Member]
Disposal Group, Including Discontinued Operation, Accounts, Notes and Loans Receivable, Net	$ 103,300,000
Disposal Group Including Discontinued Operation Accounts Notes And Loans Receivable Gross	108,700,000
Disposal Group, Including Discontinued Operation, Allowance	5,400,000
Disposal Group Including Discontinued Operation, Assets Advances Against Future Payments For Services Not Yet Performed	66,000,000.0
Disposal Group Including Discontinued Operation, Estimated Gain (Loss)	$ 26,500,000