Note 13 - Commitments and Contingencies (Details Textual) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Multiemployer Plans, Number of Participants	1,050
Corrpro [Member]
Defined Benefit Plan, Benefit Obligation, Ending Balance	$ 6.9	$ 7.9
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	$ 6.2	7.1
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	2.10%
Corrpro [Member] | Overfunded Plan [Member]
Defined Benefit Plan, Funded (Unfunded) Status of Plan, Total	$ 0.7
UNITED STATES
Defined Contribution Plan, Cost	5.2	5.7	$ 6.3
Foreign Plan [Member]
Defined Contribution Plan, Cost	0.8	1.1	1.0
Brinderson L.P. [Member] | Pre-Acquisition Matters [Member]
Loss Contingency Accrual, Ending Balance		4.0		$ 6.0
Loss Contingency Accrual, Payments	4.3	$ 0.2	0.3
Loss Contingency Accrual, Period Increase (Decrease), Total			$ 1.5
Loss Contingency Accrual, Provision	$ 0.3