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Note 9 - Debt (Details Textual) - USD ($) $ in Millions		3 Months Ended	12 Months Ended
Note 9 - Debt (Details Textual) - USD ($) $ in Millions	Apr. 05, 2021	Jun. 30, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2017	Apr. 18, 2017
Payment for Debt Extinguishment or Debt Prepayment Cost			$ 8.4	$ (0.0)	$ (0.0)
Secured Debt, Current			$ 0.4
Debt, Weighted Average Interest Rate, Net of Currency Swap Contract			0.30%
Debt Including Related Cross-currency Swap Instrument [Member]
Debt, Weighted Average Interest Rate			1.30%
The 2021 Credit Agreement [Member]
Debt Instrument, Collateral, Percentage of Stock of First Tier Foreign Subsidiaries	65.00%
Debt Instrument, Dividend Payments Allowed Per Quarter	$ 7.5
Debt Instrument, Covenant, Minimum Permitted Acquisition, Alternative Requirements for Indebtedness to EBITDA Ratio	$ 50.0
Debt Instrument, Covenant, Minimum Leverage Ratio for Dividends or Repurchase of Stock	2.50
Debt Instrument, Restrictions, Maximum Dividends Payout or Repurchase of Stock	$ 60.0
Long-term Debt, Current Maturities, Total			$ 3.8
Letters of Credit Outstanding, Amount			2.9
The 2021 Credit Agreement [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument, Variable Rate Floor	1.00%
The 2021 Credit Agreement [Member] \| Fed Funds Effective Rate Overnight Index Swap Rate [Member]
Debt Instrument, Basis Spread on Variable Rate	0.50%
The 2021 Credit Agreement [Member] \| Minimum [Member]
Debt Instrument, Other Restricted Payments Allowed Per Quarter	$ 60.0
The 2021 Credit Agreement [Member] \| Minimum [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument, Basis Spread on Variable Rate	0.10%
The 2021 Credit Agreement [Member] \| Minimum [Member] \| LIBOR on Eurocurrency Liabilities [Member]
Debt Instrument, Basis Spread on Variable Rate	1.10%
The 2021 Credit Agreement [Member] \| Maximum [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument, Basis Spread on Variable Rate	0.70%
The 2021 Credit Agreement [Member] \| Maximum [Member] \| LIBOR on Eurocurrency Liabilities [Member]
Debt Instrument, Basis Spread on Variable Rate	1.70%
The 2021 Credit Agreement [Member] \| Revolving Credit Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 450.0
Line of Credit Facility, Additional Borrowings Option	$ 275.0
Long-term Debt, Gross			168.0	10.0
Debt Instrument, Unused Borrowing Capacity, Amount			279.1
The 2021 Credit Agreement [Member] \| Revolving Credit Facility [Member] \| Minimum [Member]
Line of Credit Facility, Commitment Fee Percentage	0.15%
The 2021 Credit Agreement [Member] \| Revolving Credit Facility [Member] \| Maximum [Member]
Line of Credit Facility, Commitment Fee Percentage	0.30%
The 2021 Credit Agreement [Member] \| Term Loan [Member]
Long-term Debt, Gross			98.8
The 2021 Credit Agreement [Member] \| Term Loan [Member]
Debt Instrument, Face Amount	$ 100.0
Long-term Debt, Gross			98.8	0.0
The 2017 Credit Agreement [Member]
Debt Instrument, Covenant, Senior Secured Net Indebtedness to Adjusted EBITDA Ratio, Maximum						3.50
Line of Credit Facility, Commitment Fee Amount			0.6
The 2017 Credit Agreement [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument, Variable Rate Floor						0.00%
Senior Unsecured Notes [Member]
Debt Instrument, Face Amount							$ 300.0
Debt Instrument, Interest Rate, Stated Percentage							5.625%
Write off of Deferred Debt Issuance Cost		$ 2.9
Long-term Debt, Gross			$ 0.0	$ 300.0
Senior Unsecured Notes [Member] \| Debt Redemption Call Premium [Member]
Payment for Debt Extinguishment or Debt Prepayment Cost		$ 8.4