Note 7 - Goodwill and Intangible Assets - Balances of Acquired Intangible Assets, Excluding Goodwill (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Original cost	$ 198.6	$ 202.7
Accumulated amortization	(107.0)	(104.7)
Carrying value	91.6	98.0	$ 98.0
Customer Lists [Member]
Original cost	152.2	155.4
Accumulated amortization	(81.7)	(80.0)
Carrying value	$ 70.5	$ 75.4
Weighted average original life (in years) (Year)	15 years	15 years
Trade Names [Member]
Original cost	$ 29.6	$ 30.3
Accumulated amortization	(14.3)	(13.9)
Carrying value	$ 15.3	$ 16.4
Weighted average original life (in years) (Year)	10 years	11 years
Technology-Based Intangible Assets [Member]
Original cost	$ 16.8	$ 17.0
Accumulated amortization	(11.0)	(10.8)
Carrying value	$ 5.8	$ 6.2
Weighted average original life (in years) (Year)	11 years	11 years

Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

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Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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-Publisher FASB
-Name Accounting Standards Codification
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Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges.

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