Note 18 - Retirement Plans (Details Textual) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2005
Defined Contribution Plan, Administrative Expense	$ 3.0	$ 3.2	$ 2.6
Supplemental Employee Retirement Plan [Member]
Defined Contribution Plan Vesting Period				5 years
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	$ 4.9
Supplemental Employee Retirement Plan [Member] | Minimum [Member]
Defined Contribution Plan, Compensation Percentage Multiplier				6.50%
Supplemental Employee Retirement Plan [Member] | Maximum [Member]
Defined Contribution Plan, Compensation Percentage Multiplier				13.00%
Non-union Flat Rolled Segments’ 401K Retirement Plan [Member]
Defined Contribution Plan, Employer Matching Contribution, Percent of Match	50.00%
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	6.00%