Selected Quarterly Financial Data (unaudited) - Schedule of Quarterly Financial Information (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Jan. 03, 2016	Sep. 27, 2015	Jun. 28, 2015	Mar. 29, 2015	Dec. 28, 2014	Sep. 28, 2014	Jun. 29, 2014	Mar. 30, 2014	Jan. 03, 2016		Dec. 28, 2014	Dec. 29, 2013
Quarterly Financial Information Disclosure [Abstract]
Revenue from services	$ 1,461.6	$ 1,351.0	$ 1,385.0	$ 1,320.6	$ 1,425.0	$ 1,396.4	$ 1,410.5	$ 1,330.8	$ 5,518.2	[1]	$ 5,562.7	$ 5,413.1
Gross profit	249.5	228.2	222.3	220.3	232.6	225.4	228.1	222.3	920.3	[1]	908.4	889.5
SG&A expenses	223.0	211.6	210.8	208.2	230.0	218.3	222.2	216.0	853.6	[1]	886.5	834.5
Restructuring charges included in SG&A expenses					6.2	4.0	1.8	0.0	0.0		12.0
Net earnings	$ 34.2	$ 9.1	$ 6.8	$ 3.7	$ 17.0	$ 1.4	$ 2.8	$ 2.5	$ 53.8	[1]	$ 23.7	$ 58.9
Basic earnings per share (in dollars per share)	$ 0.88	$ 0.23	$ 0.18	$ 0.10	$ 0.44	$ 0.03	$ 0.07	$ 0.07	$ 1.39	[1]	$ 0.61	$ 1.54
Diluted earnings per share (in dollars per share)	0.88	0.23	0.18	0.10	0.44	0.03	0.07	0.07	1.39	[1]	0.61	1.54
Dividends per share (in dollars per share)	$ 0.05	$ 0.05	$ 0.05	$ 0.05	$ 0.05	$ 0.05	$ 0.05	$ 0.05	$ 0.20	[1]	$ 0.20	$ 0.20
Fiscal period duration	98 days								371 days		364 days	364 days

[1] Fiscal year included 53 weeks.