Earnings Per Share - Common Stock Reconciliation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Oct. 01, 2017	Jul. 02, 2017	Apr. 02, 2017	Jan. 01, 2017	Oct. 02, 2016	Jul. 03, 2016	Apr. 03, 2016	Dec. 31, 2017	Jan. 01, 2017	Jan. 03, 2016
Earnings Per Share [Abstract]
Net earnings	$ 17.7	$ 23.0	$ 18.7	$ 12.2	$ 19.8	$ 80.9	$ 8.9	$ 11.2	$ 71.6	$ 120.8	$ 53.8	[1]
Less: Earnings allocated to participating securities									(1.1)	(2.6)	(1.4)
Net earnings available to common shareholders									$ 70.5	$ 118.2	$ 52.4
Average common shares outstanding (millions):
Basic (in shares)									38.3	38.1	37.8	[1]
Dilutive share awards (in shares)									0.7	0.3	0.1
Diluted (in shares)									39.0	38.4	37.9	[1]
Basic earnings per share on common stock (in dollars per share)	$ 0.46	$ 0.59	$ 0.48	$ 0.31	$ 0.51	$ 2.08	$ 0.23	$ 0.29	$ 1.84	$ 3.10	$ 1.39	[1]
Diluted earnings per share on common stock (in dollars per share)	$ 0.45	$ 0.58	$ 0.47	$ 0.31	$ 0.51	$ 2.06	$ 0.23	$ 0.29	$ 1.81	$ 3.08	$ 1.39	[1]

[1] Fiscal year included 53 weeks.