Note 13 - Commitments and Contingencies (Details Textual) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Multiemployer Plans, Number of Participants	948
Corrpro [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	$ 10.2	$ 9.1
Defined Benefit Plan, Benefit Obligation, Ending Balance	$ 9.5	8.2
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	1.30%
Corrpro [Member] | Defined Benefit Plan, Overfunded Plan [Member]
Defined Benefit Plan, Funded (Unfunded) Status of Plan, Total	$ 0.7
UNITED STATES
Defined Contribution Plan, Cost	3.0	5.2	$ 5.7
Foreign Plan [Member]
Defined Contribution Plan, Cost	$ 0.3	$ 0.8	$ 1.1