|
Pension and Post-Retirement Benefit Plans - Components of Net Periodic Benefit Costs (Detail) (USD $)
In Thousands, unless otherwise specified |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
|
May 31, 2014
|
May 31, 2013
|
May 31, 2014
|
May 31, 2013
|
|
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Net periodic benefit cost | $ 1,300 | |||
|
Defined Benefit Pension Plans [Member]
|
||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Service cost | 237 | 486 | 1,113 | 1,458 |
| Interest cost | 698 | 662 | 2,168 | 1,986 |
| Expected return on plan assets | (873) | (717) | (2,499) | (2,151) |
| Amortization of prior service cost | 58 | 60 | 174 | 180 |
| Amortization of actuarial losses | 45 | 483 | 307 | 1,449 |
| Net periodic benefit cost | 165 | 974 | 1,263 | 2,922 |
|
Post-retirement Health Care Plans [Member]
|
||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Service cost | 28 | 59 | 84 | 177 |
| Interest cost | 222 | 215 | 666 | 645 |
| Amortization of prior service cost | (38) | (38) | (114) | (114) |
| Amortization of actuarial losses | 67 | 201 | ||
| Net periodic benefit cost | $ 212 | $ 303 | $ 636 | $ 909 |