CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Millions	Total	Common Class A	Common Stock	Capital in Excess of Par Value	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock
Balance at Dec. 31, 2018		$ 131.0	$ 164.5	$ 496.7	$ 2,102.8		$ (827.2)
Net earnings	$ 89.3				89.3
Issuance of share units				(6.1)
Cash dividends on stock					(37.1)
Vesting of share units				(1.9)			2.0
Stock based compensation expense				8.6
Exercises of stock options				0.1			(1.9)
Stock incentives and directors' compensation				6.1
Shares repurchased							(45.6)
Balance at Mar. 31, 2019	1,749.2	131.0	164.5	503.5	2,155.0	$ (332.1)	(872.7)
Balance at Dec. 31, 2019	1,666.8	130.9	164.5	509.0	2,323.4		(1,112.7)
Net earnings	51.7				51.7
Issuance of share units				(6.5)
Cash dividends on stock					(39.0)
Vesting of share units				(1.6)			1.6
Stock based compensation expense				8.8
Exercises of stock options				(0.1)			(1.1)
Stock incentives and directors' compensation				6.5
Shares repurchased							(56.7)
Balance at Mar. 31, 2020	$ 1,616.3	$ 130.9	$ 164.5	$ 516.1	$ 2,336.1	$ (362.4)	$ (1,168.9)