Segment Information (Revenue By Product 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
CAD [Member]
Revenue	474,608	462,307	511,582
Extended PLM [Member]
Revenue	454,299	456,285	524,741
SLM [Member]
Revenue	131,773	141,644	166,060
IoT Segment [Member]
Revenue	$ 103,359	$ 80,297	$ 52,859