Condensed Consolidated Statements of Earnings (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
Revenues	$ 574.6	$ 520.6	$ 1,130.4	$ 1,065.8
Cost of revenues	414.0	385.1	820.5	782.6
Selling, general and administrative expenses	101.1	86.0	192.8	159.5
Other expenses, net	7.9	6.8	15.5	11.7
Total expenses	523.0	477.9	1,028.8	953.8
Earnings before income taxes	51.6	42.7	101.6	112.0
Provision for income taxes	16.9	15.1	34.4	40.0
Net earnings	$ 34.7	$ 27.6	$ 67.2	$ 72.0
Basic earnings per share (in dollars per share)	$ 0.29	$ 0.23	$ 0.56	$ 0.60
Diluted earnings per share (in dollars per share)	$ 0.28	$ 0.22	$ 0.54	$ 0.58
Weighted-average shares outstanding:
Basic (in shares)	120.2	119.2	120.0	119.1
Diluted (in shares)	124.4	124.1	124.2	123.6
Dividends declared per common share (in dollars per share)	$ 0.27	$ 0.21	$ 0.54	$ 0.42