Segment Information (Revenue By Product Segment) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Revenue	$ 1,241,824	$ 1,164,039	$ 1,140,533
CAD [Member]
Revenue	499,772	474,608	462,307
Extended PLM [Member]
Revenue	483,327	454,299	456,285
IoT [Member]
Revenue	139,278	103,359	80,297
Other [Member]
Revenue	$ 119,447	$ 131,773	$ 141,644