Quarterly Financial and Market Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Schedule Of Quarterly Financial Information [Line Items]
Net sales	$ 561.0	$ 540.5	$ 547.5	$ 540.1	$ 511.7	$ 491.5	$ 491.3	$ 478.8	$ 2,189.1	$ 1,973.3	$ 2,004.3
Gross margin	150.4	143.0	144.8	142.6	142.2	135.6	139.9	134.1	580.8	551.8	564.6
Operating income	95.8	96.5	96.5	82.4	93.2	89.1	89.7	78.6	$ 371.2	$ 350.6	$ 360.1
Net income	$ 66.1	$ 80.1	$ 68.8	$ 61.6	$ 88.1	$ 69.7	$ 61.6	$ 64.6
Net income per common share:
Basic	$ 0.78	$ 0.92	$ 0.77	$ 0.68	$ 0.97	$ 0.77	$ 0.68	$ 0.71
Diluted	0.76	0.91	0.76	0.68	0.96	0.76	0.67	0.70
Maximum
Market price:
Common Stock Value during the Period	67.44	69.92	73.26	69.08	63.93	58.24	54.93	55.91
Minimum
Market price:
Common Stock Value during the Period	$ 53.76	$ 65.30	$ 63.37	$ 61.67	$ 57.43	$ 50.50	$ 49.20	$ 49.77