Consolidated Statements of Comprehensive Income Statement - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Statement of Comprehensive Income [Abstract]
Net earnings	$ 99.4	$ 188.9	$ 33.9
Other comprehensive income (loss), net of income taxes
Pension and other postretirement benefit plans activity	(0.8)	5.3	(12.8)
Unrealized foreign currency translation loss, net	(12.9)	0.0	0.0
Unrealized gain (loss) on interest rate swaps	0.0	4.2	(3.1)
Other comprehensive income (loss), net of income taxes	(13.7)	9.5	(15.9)
Comprehensive income	$ 85.7	$ 198.4	$ 18.0