Benefit Plans - Schedule of Amortization From Other Accumulated Comprehensive Income into Net Period Benefit Costs (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Aug. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, health care benefits annual rate of increase in the per capita cost	7.50%
Defined benefit plan, health care benefits annual rate of increase in the per capita cost trend rate	5.00%
Qualified Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Amortization of prior service cost (benefit)	$ 1,597
Amortization of net actuarial loss	18,576
Non-Qualified Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Amortization of prior service cost (benefit)	229
Amortization of net actuarial loss	951
Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Amortization of prior service cost (benefit)	(120)
Amortization of net actuarial loss	$ (374)

The amounts in accumulated other comprehensive income related to gains and losses that are not recognized immediately and are expected to be recognized as components of net periodic benefit cost over the next fiscal year that follows the most recent annual statement of financial position presented.

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The amounts in accumulated other comprehensive income related to prior service cost or credit expected to be recognized as components of net periodic benefit cost over the next fiscal year that follows the most recent annual statement of financial position presented.

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- Definition

The assumed health care cost trend rate for the next year used to measure the expected cost of benefits covered by the plan (gross eligible charges). This is based upon the annual rate of change in the cost of health care benefits currently provided by the postretirement benefit plan, due to factors other than changes in the composition of the plan population by age and dependency status.

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