Post-Retirement Benefits - Schedule of Fair Value of Plan Assets (Detail) - Employee Pension Plan [Member] - USD ($) $ in Thousands	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 29,673	$ 24,847	$ 26,133
Carrying Amount [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	29,673	24,847
Estimate of Fair Value Measurement [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	119	313
Estimate of Fair Value Measurement [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	29,554	24,534
Equity Mutual Funds And Common/Collective Trusts [Member] | Carrying Amount [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	20,140	15,624
Equity Mutual Funds And Common/Collective Trusts [Member] | Estimate of Fair Value Measurement [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	20,140	15,624
Fixed Income Common/Collective Trusts [Member] | Carrying Amount [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	9,414	8,910
Fixed Income Common/Collective Trusts [Member] | Estimate of Fair Value Measurement [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	9,414	8,910
Cash Equivalents [Member] | Carrying Amount [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	119	313
Cash Equivalents [Member] | Estimate of Fair Value Measurement [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 119	$ 313