Consolidated Statements of Earnings (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Apr. 01, 2018	Apr. 02, 2017
Income Statement [Abstract]
Revenue from services	$ 1,369.9	$ 1,289.7
Cost of services	1,131.7	1,058.1
Gross profit	238.2	231.6
Selling, general and administrative expenses	226.2	215.2
Earnings from operations	12.0	16.4
Gain on investment in Persol Holdings	23.7	0.0
Other expense, net	(1.7)	(1.6)
Earnings before taxes and equity in net earnings (loss) of affiliate	34.0	14.8
Income tax expense	6.4	2.7
Net earnings before equity in net earnings (loss) of affiliate	27.6	12.1
Equity in net earnings (loss) of affiliate	1.5	0.1
Net earnings	$ 29.1	$ 12.2
Basic earnings per share (in dollars per share)	$ 0.74	$ 0.31
Diluted earnings per share (in dollars per share)	0.74	0.31
Dividends per share (in dollars per share)	$ 0.075	$ 0.075
Average shares outstanding (millions):
Basic (in shares)	38.6	38.3
Diluted (in shares)	38.9	38.7