Segment Information (Revenue By Geographic Segment) (Details) - USD ($) $ in Thousands		12 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Revenue		$ 1,164,039	$ 1,140,533	$ 1,255,242
Total long-lived intangible assets		63,600	67,113	65,162
Americas [Member]
Revenue	[1]	500,879	487,594	530,311
Total long-lived intangible assets	[2]	47,055	48,281	47,509
Europe [Member]
Revenue	[3]	435,183	424,268	467,805
Total long-lived intangible assets		6,284	6,915	7,424
Asia Pacific [Member]
Revenue	[3]	227,977	228,671	257,126
Total long-lived intangible assets		10,261	11,917	10,229
United States [Member]
Revenue		475,500	463,100	500,600
Germany [Member]
Revenue		$ 164,700	$ 167,200	$ 177,100

[1] Includes revenue in the United States totaling $475.5 million, $463.1 million and $500.6 million for 2017, 2016 and 2015, respectively.

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

[3] Includes revenue in Germany totaling $164.7 million, $167.2 million and $177.1 million for 2017, 2016 and 2015, respectively.