Goodwill and Acquired Intangible Assets (Goodwill and Acquired Intangible Assets) (Details) (USD $) In Thousands, unless otherwise specified						12 Months Ended								12 Months Ended				12 Months Ended				12 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2011	Sep. 30, 2013 Purchased Software [Member]		Sep. 30, 2012 Purchased Software [Member]		Sep. 30, 2013 Capitalized Software [Member]		Sep. 30, 2012 Capitalized Software [Member]		Sep. 30, 2013 Customer Lists and Relationships [Member]		Sep. 30, 2012 Customer Lists and Relationships [Member]		Sep. 30, 2013 Trademarks And Trade Names [Member]		Sep. 30, 2012 Trademarks And Trade Names [Member]		Sep. 30, 2013 Other [Member]		Sep. 30, 2012 Other [Member]
Goodwill (not amortized), Net Book Value	$ 769,095		$ 610,347		$ 613,394
Intangible assets with finite lives (amortized), Gross Carrying Amount	578,088	[1]	441,590	[1]		233,566	[1]	177,166	[1]	22,877	[1]	22,877	[1]	304,434	[1]	227,097	[1]	13,427	[1]	11,013	[1]	3,784	[1]	3,437	[1]
Intangible assets with finite lives (amortized), Accumulated Amortization	304,967	[1]	255,705	[1]		148,127	[1]	127,250	[1]	22,877	[1]	22,877	[1]	120,338	[1]	93,215	[1]	10,097	[1]	8,967	[1]	3,528	[1]	3,396	[1]
Intangible assets with finite lives (amortized), Net Book Value	273,121	[1]	185,885	[1]		85,439	[1]	49,916	[1]	0	[1]	0	[1]	184,096	[1]	133,882	[1]	3,330	[1]	2,046	[1]	256	[1]	41	[1]
Total goodwill and acquired intangible assets	$ 1,042,216		$ 796,232
Weighted average useful lives (in years)						8 years								10 years				7 years				3 years

[1] The weighted average useful lives of purchased software, customer lists and relationships, trademarks and trade names and other intangible assets with a remaining net book value are 8 years, 10 years, 7 years and 3 years, respectively.