Quarterly Financial and Market Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule Of Quarterly Financial Information [Line Items]
Net sales	$ 483.5	$ 500.5	$ 522.6	$ 497.7	$ 464.9	$ 448.8	$ 475.7	$ 471.8	$ 2,004.3	$ 1,861.2	$ 1,855.5
Gross margin	135.6	135.7	150.3	143.0	127.8	124.1	139.1	141.8	564.6	532.8	508.8
Operating income	87.0	89.1	100.1	83.9	81.2	78.0	90.6	82.6	$ 360.1	$ 332.4	$ 305.8
Net income	$ 59.5	$ 68.2	$ 66.1	$ 56.0	$ 53.9	$ 53.5	$ 61.7	$ 68.1
Net income per common share:
Basic	$ 0.65	$ 0.74	$ 0.71	$ 0.60	$ 0.57	$ 0.56	$ 0.64	$ 0.71
Diluted	0.64	0.72	0.70	0.59	0.56	0.55	0.63	0.70
Maximum
Market price:
Common Stock Value during the Period	54.97	45.68	46.26	45.40	48.20	54.36	51.58	51.11
Minimum
Market price:
Common Stock Value during the Period	$ 42.04	$ 40.82	$ 39.15	$ 38.38	$ 42.38	$ 43.89	$ 48.19	$ 40.05