Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Receivable, allowance	$ 5.1	$ 4.6
Accumulated depreciation	$ 267.6	$ 252.0
Common stock, par value (in dollars per share)	$ 0.375	$ 0.375
Common stock, shares authorized (in shares)	60,000,000	60,000,000
Common stock, shares issued (in shares)	18,583,237	18,503,805
Common stock, shares outstanding (in shares)	18,583,237	18,503,805

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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