Quarterly Financial Information (unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jul. 01, 2018	Apr. 01, 2018	Dec. 31, 2017	Oct. 01, 2017	Jul. 02, 2017	Apr. 02, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information (unaudited)
Revenue	$ 387.6	$ 390.9	$ 407.9	$ 378.5	$ 366.3	$ 364.7	$ 378.5	$ 347.2	$ 1,564.9	$ 1,456.7	$ 1,398.4
Gross profit	165.9	164.5	169.4	156.7	149.2	152.7	156.7	143.8	656.5	602.4	565.6
Net income (loss)	$ 32.3	$ 31.5	$ 36.0	$ 28.2	$ (2.3)	$ 26.5	$ 27.2	$ 21.7	$ 128.0	$ 73.1	$ 84.2
BASIC EPS
Net income (in dollars per share)	$ 0.94	$ 0.92	$ 1.05	$ 0.82	$ (0.07)	$ 0.77	$ 0.79	$ 0.63	$ 3.73	$ 2.12	$ 2.45
DILUTED EPS
Net income (in dollars per share)	0.94	0.92	1.05	0.82	(0.07)	0.77	0.79	0.63	3.73	2.12	2.44
Dividends declared per common share (in dollars per share)	$ 0.21	$ 0.21	$ 0.21	$ 0.19	$ 0.19	$ 0.19	$ 0.19	$ 0.18	$ 0.82	$ 0.75	$ 0.71