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, 2014		Sep. 30, 2013		Sep. 30, 2012	Sep. 30, 2014 Purchased Software [Member]		Sep. 30, 2013 Purchased Software [Member]		Sep. 30, 2014 Capitalized Software [Member]		Sep. 30, 2013 Capitalized Software [Member]		Sep. 30, 2014 Customer Lists and Relationships [Member]		Sep. 30, 2013 Customer Lists and Relationships [Member]		Sep. 30, 2014 Trademarks And Trade Names [Member]		Sep. 30, 2013 Trademarks And Trade Names [Member]		Sep. 30, 2014 Other [Member]		Sep. 30, 2013 Other [Member]
Goodwill (not amortized), Net Book Value	$ 1,012,527		$ 769,095		$ 610,347
Intangible assets with finite lives (amortized), Gross Carrying Amount	684,015	[1]	578,088	[1]		278,012	[1]	233,566	[1]	22,877	[1]	22,877	[1]	360,530	[1]	304,434	[1]	18,479	[1]	13,427	[1]	4,117	[1]	3,784	[1]
Intangible assets with finite lives (amortized), Accumulated Amortization	347,142	[1]	304,967	[1]		162,259	[1]	148,127	[1]	22,877	[1]	22,877	[1]	147,469	[1]	120,338	[1]	10,964	[1]	10,097	[1]	3,573	[1]	3,528	[1]
Intangible assets with finite lives (amortized), Net Book Value	336,873	[1]	273,121	[1]		115,753	[1]	85,439	[1]	0	[1]	0	[1]	213,061	[1]	184,096	[1]	7,515	[1]	3,330	[1]	544	[1]	256	[1]
Total goodwill and acquired intangible assets	$ 1,349,400		$ 1,042,216
Weighted average useful lives (in years)						9 years								10 years				9 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 9 years, 10 years, 9 years and 3 years, respectively.