Note 7 - Contract Assets and Liabilities (Details Textual) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Contract with Customer, Liability, Revenue Recognized	$ 146.4	$ 95.8
Contract with Customer, Liability, Cumulative Catch-up Adjustment to Revenue, Change in Estimate of Transaction Price	72.1	43.9
Aggregate Affirmative Claim Recovery Estimate Included in Contract Asset and Liability	$ 42.4	$ 76.5	$ 37.7