Property And Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Property, Plant and Equipment [Abstract]
Computer hardware and software	$ 246,756	$ 230,591
Furniture and fixtures	18,370	19,025
Leasehold improvements	38,005	36,896
Gross property and equipment	303,131	286,512
Accumulated depreciation and amortization	(237,969)	(218,729)
Net property and equipment	65,162	67,783	$ 64,652
Depreciation expense	$ 28,900	$ 27,100	$ 31,500