Note 7 - Debt (Details Textual) - USD ($) $ in Thousands | Oct. 23, 2020 | Sep. 23, 2020 | Sep. 30, 2020 | Sep. 30, 2019 | Apr. 30, 2020 | Dec. 31, 2019 | Aug. 31, 2015 |
Letters of Credit Outstanding, Amount | | | $ 36,700 | | | $ 35,200 | |
Interest Rate Swap [Member] | | | | | | | |
Derivative, Fixed Interest Rate | | | | | | | 4.20% |
Variable Rate Note [Member] | | | | | | | |
Debt Instrument, Face Amount | | | | | | | $ 28,000 |
Lenders [Member] | | | | | | | |
Line of Credit Facility, Maximum Borrowing Capacity | | | $ 95,000 | | | | |
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage | | | 0.25% | | | | |
Percent of Eligible Accounts Receivable | | | 85.00% | | | | |
Percent of Appraised Net Orderly Liquidation, Value of Eligible Revenue Equipment | | | 85.00% | | | | |
Percent of Net Book Value of Eligible Revenue Equipment | | | 95.00% | | | | |
Line of Credit Facility, Availability as Percentage of Revolver Commitment | | | 35.00% | | | | |
Line of Credit Facility, Revolver Commitment, Amount | | | $ 45,000 | | | | |
Percent of Appraised Fair Market Value of Eligible Real Estate | | | 75.00% | | | | |
Long-term Line of Credit, Total | | | $ 0 | | | | |
Letters of Credit Outstanding, Amount | | | 36,700 | | | | |
Line of Credit Facility, Remaining Borrowing Capacity | | | 58,300 | | | | |
Fixed Charge Coverage Requirement | | | 0 | $ 0 | | | |
Debt, Secured with a Cross Default Feature | | | $ 60,300 | | $ 177,300 | | |
Lenders [Member] | Federal Funds Rate [Member] | Base Rate Loans [Member] | | | | | | | |
Debt Instrument, Basis Spread on Variable Rate | | | 0.50% | | | | |
Lenders [Member] | London Interbank Offered Rate (LIBOR) [Member] | Base Rate Loans [Member] | | | | | | | |
Debt Instrument, Basis Spread on Variable Rate | | | 1.00% | | | | |
Lenders [Member] | Applicable Margin [Member] | Base Rate Loans [Member] | Minimum [Member] | | | | | | | |
Debt Instrument, Basis Spread on Variable Rate | | | 0.50% | | | | |
Lenders [Member] | Applicable Margin [Member] | Base Rate Loans [Member] | Maximum [Member] | | | | | | | |
Debt Instrument, Basis Spread on Variable Rate | | | 1.00% | | | | |
Lenders [Member] | Applicable Margin [Member] | LIBOR Loans [Member] | Minimum [Member] | | | | | | | |
Debt Instrument, Basis Spread on Variable Rate | | | 1.50% | | | | |
Lenders [Member] | Applicable Margin [Member] | LIBOR Loans [Member] | Maximum [Member] | | | | | | | |
Debt Instrument, Basis Spread on Variable Rate | | | 2.00% | | | | |
Lenders [Member] | Revolving Credit Facility [Member] | | | | | | | |
Line of Credit Facility, Maximum Borrowing Capacity | | | $ 95,000 | | | | |
Line of Credit Facility, Maximum Increase in Borrowing Capacity | | | 50,000 | | | | |
Lenders [Member] | Revolving Credit Facility [Member] | Base Rate Loans [Member] | | | | | | | |
Long-term Line of Credit, Total | | | 0 | | | | |
Lenders [Member] | Letter of Credit [Member] | | | | | | | |
Line of Credit Facility, Maximum Borrowing Capacity | | | 95,000 | | | | |
Line of Credit Facility, Borrowing Capacity, Percentage of Aggregate Commitments | | | $ 10,000 | | | | |
Lenders [Member] | Swing Line Sub Facility [Member] | | | | | | | |
Percent of Aggregate Commitments under Credit Facility | | | 10.00% | | | | |
Lenders [Member] | Subsequent Event [Member] | | | | | | | |
Line of Credit Facility, Maximum Borrowing Capacity | $ 110,000 | | | | | | |
Percent of Eligible Accounts Receivable | 87.50% | | | | | | |
Percent of Net Book Value of Eligible Revenue Equipment | 100.00% | | | | | | |
Line of Credit Facility, Availability as Percentage of Revolver Commitment | 40.90% | | | | | | |
Line of Credit Facility, Maximum Commitment Value | $ 10,400 | | | | | | |
Percent of Appraised Fair Market Value of Eligible Real Estate | 80.00% | | | | | | |
Lenders [Member] | Subsequent Event [Member] | Applicable Margin [Member] | Base Rate Loans [Member] | Minimum [Member] | | | | | | | |
Debt Instrument, Basis Spread on Variable Rate | 0.25% | | | | | | |
Lenders [Member] | Subsequent Event [Member] | Applicable Margin [Member] | Base Rate Loans [Member] | Maximum [Member] | | | | | | | |
Debt Instrument, Basis Spread on Variable Rate | 0.75% | | | | | | |
Lenders [Member] | Subsequent Event [Member] | Applicable Margin [Member] | LIBOR Loans [Member] | Minimum [Member] | | | | | | | |
Debt Instrument, Basis Spread on Variable Rate | 1.25% | | | | | | |
Lenders [Member] | Subsequent Event [Member] | Applicable Margin [Member] | LIBOR Loans [Member] | Maximum [Member] | | | | | | | |
Debt Instrument, Basis Spread on Variable Rate | 1.75% | | | | | | |
Lenders [Member] | Subsequent Event [Member] | Revolving Credit Facility [Member] | | | | | | | |
Line of Credit Facility, Maximum Borrowing Capacity | $ 110,000 | | | | | | |
Lenders [Member] | Subsequent Event [Member] | Letter of Credit [Member] | | | | | | | |
Line of Credit Facility, Maximum Borrowing Capacity | $ 105,000 | | | | | | |
TBK Bank [Member] | Draw Note [Member] | | | | | | | |
Line of Credit Facility, Maximum Borrowing Capacity | | $ 45,000 | | | | | |
Debt Instrument, Collateral Amount | | $ 60,000 | | | | | |
TBK Bank [Member] | London Interbank Offered Rate (LIBOR) [Member] | Draw Note [Member] | | | | | | | |
Debt Instrument, Basis Spread on Variable Rate | | 1.50% | | | | | |
TBK Bank [Member] | London Interbank Offered Rate (LIBOR) [Member] | Draw Note [Member] | Minimum [Member] | | | | | | | |
Debt Instrument, Basis Spread on Variable Rate | | 0.25% | | | | | |