Equity Investment (Summary of Investment in Joint Venture, Income Statement Data) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Schedule of Equity Method Investments [Line Items]
Net sales	$ 280.0	$ 203.2	$ 531.9	$ 451.9
Gross profit	104.9	67.8	192.4	159.1
Net earnings	55.1	50.3	90.5	(175.9)
WAVE [Member] | Equity Method Investment, Nonconsolidated Investee or Group of Investees [Member]
Schedule of Equity Method Investments [Line Items]
Net sales	108.7	75.3	207.3	170.7
Gross profit	64.6	41.4	123.5	96.3
Net earnings	$ 49.5	$ 29.1	$ 94.1	$ 69.9