Fair Value (Financial Assets and Liabilities Not Required to Be Measured at Fair Value) (Details) (USD $) In Thousands, unless otherwise specified	Feb. 28, 2014		Aug. 31, 2013
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt and Capital Lease Obligations	$ 1,283,535		$ 1,284,042
$400 million notes at 6.50% due July 2017 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt and Capital Lease Obligations			411,518
$400 million notes at 6.50% due July 2017 [Member] | Level 2 [Member] | Carrying Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt and Capital Lease Obligations	410,032		411,518
$400 million notes at 6.50% due July 2017 [Member] | Level 2 [Member] | Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt and Capital Lease Obligations	446,800	[1]	443,646	[1]
$500 million notes at 7.35% due August 2018 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt and Capital Lease Obligations			522,930
$500 million notes at 7.35% due August 2018 [Member] | Level 2 [Member] | Carrying Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt and Capital Lease Obligations	520,617		522,930
$500 million notes at 7.35% due August 2018 [Member] | Level 2 [Member] | Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt and Capital Lease Obligations	570,190	[1]	570,429	[1]
$330 million notes at 4.875% due May 2023 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt and Capital Lease Obligations			330,000
$330 million notes at 4.875% due May 2023 [Member] | Level 2 [Member] | Carrying Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt and Capital Lease Obligations	330,000		330,000
$330 million notes at 4.875% due May 2023 [Member] | Level 2 [Member] | Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt and Capital Lease Obligations	$ 323,400	[1]	$ 298,650	[1]

[1] (1) The fair value of the notes is calculated based on indicated market values.