Marketable Securities (Details) (USD $) In Thousands, unless otherwise specified	Nov. 30, 2013	Aug. 31, 2013
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity securities, current	$ 128,736	$ 105,809
Held-to-maturity securities, noncurrent	102,779	37,995
Marketable securities, current	128,736	105,809
Marketable securities, noncurrent	108,725	43,941
US States and Political Subdivisions Debt Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity securities, current	57,169	69,621
Held-to-maturity securities, noncurrent	43,879	24,070
Commercial Paper [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity securities, current	28,109	9,828
Held-to-maturity securities, noncurrent	0	0
Corporate Debt Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity securities, current	26,480	24,503
Held-to-maturity securities, noncurrent	56,206	13,925
Other Debt [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity securities, current	16,978	1,857
Held-to-maturity securities, noncurrent	2,694	0
Auction Rate Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Available-for-sale securities, current	0	0
Available-for-sale securities, noncurrent	$ 5,946	$ 5,946

- Definition

Investments in debt and equity securities which are categorized neither as held-to-maturity nor trading and which are intended to be sold or mature more than one year from the balance sheet date or operating cycle, if longer. Such securities are reported at fair value; unrealized gains (losses) related to Available-for-sale Securities are excluded from earnings and reported in a separate component of shareholders' equity (other comprehensive income), unless the Available-for-sale security is designated as a hedge or is determined to have had an other than temporary decline in fair value below its amortized cost basis. All or a portion of the unrealized holding gain (loss) of an Available-for-sale security that is designated as being hedged in a fair value hedge is recognized in earnings during the period of the hedge, as are other than temporary declines in fair value below the cost basis for investments in equity securities and debt securities that an entity intends to sell or it is more likely than not that it will be required to sell before the recovery of its amortized cost basis. Other than temporary declines in fair value below the cost basis for debt securities categorized as Available-for-sale that an entity does not intend to sell and for which it is not more likely than not that the entity will be required to sell before the recovery of its amortized cost basis are bifurcated into credit losses and losses related to all other factors. Other than temporary declines in fair value below cost basis related to credit losses are recognized in earnings, and losses related to all other factors are recognized in other comprehensive income.

+ References+ Details