Summary of Other Postretirement Benefit Plans (Detail) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2014
Amounts recognized on the Consolidated Balance Sheet
Pensions and other postretirement benefits	$ (2,076,143)	$ (1,699,197)
Other Postretirement Benefit Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Expense related to other postretirement benefits	8,754	4,340	$ 4,478
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at beginning of year	75,953	76,207
Service cost	591	632
Interest cost	2,834	2,723
Special termination cost	4,521	0
Actuarial (gain) loss	10,217	655
Benefits paid	(4,331)	(4,264)
Benefit obligation at end of year	89,785	75,953	$ 76,207
Funded status	(89,785)	(75,953)
Amounts recognized on the Consolidated Balance Sheet
Other accrued liabilities	(6,216)	(5,629)
Pensions and other postretirement benefits	(83,569)	(70,324)
Net amount recognized	(89,785)	(75,953)
Amounts recognized in Accumulated Other Comprehensive (Loss)
Net actuarial loss	22,914	13,626
Prior service (credit)	(556)	(676)
Net amount recognized	22,358	$ 12,950
Defined Benefit Plan, Amount to be Amortized from Accumulated Other Comprehensive Income (Loss) Next Fiscal Year [Abstract]
Estimated amount of net actuarial loss that will be amortized from accumulated other comprehensive (loss) income into net periodic benefit pension cost	2,101
Estimated amount of prior service credit that will be amortized from accumulated other comprehensive (loss) income into net periodic benefit pension cost	$ (121)