Employee Benefit Plans - Major Categories of Assets Measured at Fair Value on Recurring Basis (Detail) - Pension Plan - USD ($) $ in Thousands	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2014
Defined Benefit Plan Disclosure
Defined benefit plan, fair value of plan assets	$ 584,167	$ 594,769	$ 557,271
Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Defined benefit plan, fair value of plan assets	6,841	6,742
Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Defined benefit plan, fair value of plan assets	577,326	588,027
Investment Funds
Defined Benefit Plan Disclosure
Defined benefit plan, fair value of plan assets	578,276	589,050
Investment Funds | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Defined benefit plan, fair value of plan assets	1,238	1,307
Investment Funds | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Defined benefit plan, fair value of plan assets	577,038	587,743
Debt Securities
Defined Benefit Plan Disclosure
Defined benefit plan, fair value of plan assets		113
Debt Securities | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Defined benefit plan, fair value of plan assets		113
Insurance Contracts
Defined Benefit Plan Disclosure
Defined benefit plan, fair value of plan assets	3,150	3,538
Insurance Contracts | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Defined benefit plan, fair value of plan assets	2,862	3,254
Insurance Contracts | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Defined benefit plan, fair value of plan assets	288	284
Cash and Cash Equivalents.
Defined Benefit Plan Disclosure
Defined benefit plan, fair value of plan assets	2,741	2,068
Cash and Cash Equivalents. | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Defined benefit plan, fair value of plan assets	$ 2,741	$ 2,068