Segment Information (Revenue By Geographic Segment) (Details) (USD $) In Thousands	12 Months Ended
	Sep. 30, 2011		Sep. 30, 2010		Sep. 30, 2009
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 1,166,949		$ 1,010,049		$ 938,185
Total long-lived tangible assets	62,569		58,064		58,105
Americas [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	429,215	[1]	385,853	[1]	351,826	[1]
Total long-lived tangible assets	42,767	[2]	38,417	[2]	41,184	[2]
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	466,532	[3]	388,513	[3]	372,436	[3]
Total long-lived tangible assets	5,693		5,753		6,181
Pacific Rim [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	148,000		131,632		109,833
Japan [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	123,202		104,051		104,090
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	409,800		370,800		337,400
Germany [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	176,600		143,800		120,800
Asia-Pacific [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total long-lived tangible assets	$ 14,109		$ 13,894		$ 10,740

[1] Includes revenue in the United States totaling $409.8 million, $370.8 million and $337.4 million for 2011, 2010 and 2009, respectively.

[2] Substantially all of the Americas long-lived tangible assets are located in the United States.

[3] Includes revenue in Germany totaling $176.6 million, $143.8 million and $120.8 million for 2011, 2010 and 2009, respectively.