Quarterly Financial and Market Data (Unaudited) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Schedule Of Quarterly Financial Information [Line Items]
Net sales	$ 471.8	$ 451.9	$ 470.1	$ 461.7	$ 426.8	$ 412.3	$ 422.6	$ 416.5	$ 1,855.5	$ 1,678.2	$ 1,578.2
Gross margin	128.5	122.0	129.1	129.2	113.1	112.1	116.8	112.0	508.8	454.0	406.7
Other income, net									(6.0)		9.5
Operating income	77.1	79.0	75.1	74.6	67.0	69.0	71.9	63.0	305.8	270.9	248.8
Net income	$ 52.9	$ 55.8	$ 50.6	$ 50.1	$ 47.1	$ 48.7	$ 48.5	$ 43.6
Net income per common share:
Basic	$ 0.55	$ 0.58	$ 0.52	$ 0.51	$ 0.47	$ 0.49	$ 0.49	$ 0.43	$ 2.16	$ 1.88	$ 1.64
Diluted	$ 0.54	$ 0.57	$ 0.51	$ 0.50	$ 0.46	$ 0.48	$ 0.48	$ 0.43	$ 2.12	$ 1.84	$ 1.61
Maximum
Market price:
Common Stock Value during the Period	$ 43.84	$ 41.73	$ 44.27	$ 46.40	$ 44.69	$ 39.67	$ 35.46	$ 30.23
Minimum
Market price:
Common Stock Value during the Period	$ 36.92	$ 37.03	$ 39.31	$ 40.28	$ 38.09	$ 33.88	$ 27.64	$ 26.50