Quarterly Financial and Market Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule Of Quarterly Financial Information [Line Items]
Net sales	$ 464.9	$ 448.8	$ 475.7	$ 471.8	$ 471.8	$ 451.9	$ 470.1	$ 461.7	$ 1,861.2	$ 1,855.5	$ 1,678.2
Gross margin	127.8	124.1	139.1	141.8	128.5	122.0	129.1	129.2	532.8	508.8	454.0
Operating income	81.2	78.0	90.6	82.6	77.1	79.0	75.1	74.6	$ 332.4	$ 305.8	$ 270.9
Net income	$ 53.9	$ 53.5	$ 61.7	$ 68.1	$ 52.9	$ 55.8	$ 50.6	$ 50.1
Net income per common share:
Basic	$ 0.57	$ 0.56	$ 0.64	$ 0.71	$ 0.55	$ 0.58	$ 0.52	$ 0.51	$ 2.48	$ 2.16	$ 1.88
Diluted	0.56	0.55	0.63	0.70	0.54	0.57	0.51	0.50	$ 2.44	$ 2.12	$ 1.84
Maximum
Market price:
Common Stock Value during the Period	48.20	54.36	51.58	51.11	43.84	41.73	44.27	46.40
Minimum
Market price:
Common Stock Value during the Period	$ 42.38	$ 43.89	$ 48.19	$ 40.05	$ 36.92	$ 37.03	$ 39.31	$ 40.28