Fair Value (Financial Assets and Financial Liabilities Measured at Fair Value on Recurring Basis) (Details) (USD $) In Thousands, unless otherwise specified	Nov. 30, 2012		Aug. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	$ 2,052	[1]	$ 1,875	[1]
Derivative liabilities	2,867	[1]	3,547	[1]
Fair value, measurements, recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market investments	192,417		172,462
Derivative assets	2,052		1,875
Nonqualified benefit plan assets	54,208	[2]	52,929	[2]
Derivative liabilities	2,867		3,547
Nonqualified benefit plan liabilities	75,561	[2]	76,952	[2]
Fair value, inputs, level 1 [Member] | Fair value, measurements, recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market investments	192,417		172,462
Derivative assets	1,467		407
Nonqualified benefit plan assets	54,208	[2]	52,929	[2]
Derivative liabilities	2,051		993
Nonqualified benefit plan liabilities	0	[2]	0	[2]
Fair value, inputs, level 2 [Member] | Fair value, measurements, recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market investments	0		0
Derivative assets	585		1,468
Nonqualified benefit plan assets	0	[2]	0	[2]
Derivative liabilities	816		2,554
Nonqualified benefit plan liabilities	75,561	[2]	76,952	[2]
Fair value, inputs, level 3 [Member] | Fair value, measurements, recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market investments	0		0
Derivative assets	0		0
Nonqualified benefit plan assets	0	[2]	0	[2]
Derivative liabilities	0		0
Nonqualified benefit plan liabilities	$ 0	[2]	$ 0	[2]

[1] * Derivative assets and liabilities do not include the hedged items designated as fair value hedges.

[2] The Company provides a nonqualified benefit restoration plan to certain eligible executives equal to amounts that would have been available under tax qualified Employee Retirement Income Security Act ("ERISA") plans but for limitations of ERISA, tax laws and regulations. Though under no obligation to fund this plan, the Company has segregated assets in a trust. The plan assets and liabilities consist of securities included in various mutual funds.