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Employee Benefit Plans - Additional Information (Detail) - USD ($)
$ in Millions
 12 Months Ended
Jun. 30, 2015
Jun. 30, 2014
Jun. 30, 2013
Defined Benefit Plan Disclosure [Line Items]      
Defined Contribution Saving Plan costs recorded $ 24.9 $ 22.1 $ 21.6
Supplemental Employee Retirement Plan [Member] | Officer [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Postretirement benefit expense 2.7 2.9 3.4
Benefit obligation 25.3 21.0 17.0
Supplemental Employee Retirement Plan [Member] | Executive [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Postretirement benefit expense 0.6 0.5 0.5
Benefit obligation 2.7 2.3 1.5
Postretirement Health Coverage [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Postretirement benefit expense 0.2 0.2 0.2
Benefit obligation 3.9 $ 3.2 $ 3.0
United States Postretirement Benefit Plan of US Entity [Member] | Executive Retirement And Savings Plan [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined Contribution Saving Plan costs recorded $ 0.4