Consolidated Statements of Earnings (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jul. 03, 2016	Jun. 28, 2015	Jul. 03, 2016	Jun. 28, 2015
Income Statement [Abstract]
Revenue from services	$ 1,375.5	$ 1,385.0	$ 2,724.6	$ 2,705.6
Cost of services	1,145.0	1,162.7	2,261.4	2,263.0
Gross profit	230.5	222.3	463.2	442.6
Selling, general and administrative expenses	220.6	210.8	438.6	419.0
Earnings from operations	9.9	11.5	24.6	23.6
Other expense, net	0.2	1.0	1.0	3.5
Earnings before taxes	9.7	10.5	23.6	20.1
Income tax expense	0.8	3.7	3.5	9.6
Net earnings	$ 8.9	$ 6.8	$ 20.1	$ 10.5
Basic earnings per share (in dollars per share)	$ 0.23	$ 0.18	$ 0.52	$ 0.27
Diluted earnings per share (in dollars per share)	0.23	0.18	0.51	0.27
Dividends per share (in dollars per share)	$ 0.075	$ 0.05	$ 0.125	$ 0.10
Average shares outstanding (millions):
Basic (in shares)	38.0	37.7	38.0	37.7
Diluted (in shares)	38.3	37.8	38.2	37.8