Condensed Consolidated Statements of Shareholders' Equity - USD ($) $ in Millions	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock Common Stock	Common Stock Class B Common Stock	Additional Paid-in Capital	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Loss
Beginning balance at Jun. 30, 2020	$ 388.2	$ 2.1	$ 40.3	$ 5.1	$ 227.6	$ 197.6	$ 2.1	$ (82.4)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	42.3					42.3
Other comprehensive income (loss), net of income taxes	7.1							7.1
Stock issued under various incentive plans, net of forfeitures	0.4		0.1		0.3
Purchases of Company stock	(0.4)				(0.4)
Share-based compensation	$ 8.8				8.8
Cumulative effect adjustment	Accounting Standards Update 2016-13 [Member]
Ending balance at Sep. 30, 2020	$ 448.5		40.4	5.1	236.3	242.0		(75.3)
Beginning balance at Jun. 30, 2021	652.1		40.6	5.1	178.5	506.3		(78.4)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	24.8					24.8
Other comprehensive income (loss), net of income taxes	(3.7)							(3.7)
Stock issued under various incentive plans, net of forfeitures	6.0		0.3		5.7
Purchases of Company stock	(8.5)		(0.2)		(8.3)
Share-based compensation	9.8				9.8
Ending balance at Sep. 30, 2021	$ 680.5		$ 40.7	$ 5.1	$ 185.7	$ 531.1		$ (82.1)