Note 7 - Fair Value Measurements (Details Textual) - Senior Notes [Member] - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Long-Term Debt, Total	$ 945.6	$ 945.2
Fair Value, Nonrecurring [Member]
Long-Term Debt, Total	945.6	945.2
Long-Term Debt, Fair Value	$ 960.1	$ 1,040.0

Amount, excluding unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

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