Note 11 - Goodwill and Other Intangible Assets (Details Textual) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Feb. 28, 2022	Dec. 31, 2021
Goodwill, Ending Balance	$ 111,700		$ 111,700			$ 100,500
Acquired Finite-lived Intangible Asset, Residual Value	0		0
Amortization of Intangible Assets	4,800	$ 3,500	8,500	$ 7,200
Finite-Lived Intangible Asset, Expected Amortization, Remainder of Fiscal Year	18,200		18,200
Finite-Lived Intangible Asset, Expected Amortization, Year One	19,400		19,400
Finite-Lived Intangible Asset, Expected Amortization, Year Two	18,200		18,200
Finite-Lived Intangible Asset, Expected Amortization, Year Three	17,900		17,900
Finite-Lived Intangible Asset, Expected Amortization, Year Four	$ 17,100		$ 17,100
Zenith Freight Lines, LLC [Member]
Goodwill, Ending Balance					$ 11,200
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles					$ 42,700