Consolidated Statements of Operations (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Income Statement [Abstract]
Revenues from services	$ 5,143.3	$ 4,924.4
Cost of services	4,246.2	4,156.3
Gross profit	897.1	768.1
Selling and administrative expenses	758.4	669.7
Operating profit	138.7	98.4
Interest and other expenses, net	2.7	5.4
Earnings before income taxes	136.0	93.0
Provision for income taxes	44.4	31.0
Net earnings	$ 91.6	$ 62.0
Net earnings (loss) per share - basic	$ 1.71	$ 1.12
Net earnings (loss) per share - diluted	$ 1.68	$ 1.11
Weighted average shares - basic (in shares)	53.6	55.1
Weighted average shares - diluted (in shares)	54.4	55.7