Income Taxes (Schedule Of Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Income Tax Disclosure [Abstract]
Net operating loss carryforwards	$ 143,793	$ 100,033
Foreign tax credits	21,099	18,041
Capitalized research and development expense	13,044	22,504
Pension benefits	12,107	14,348
Deferred revenue	59,022	65,145
Stock-based compensation	25,360	19,846
Other reserves not currently deductible	16,905	25,993
Amortization of intangible assets	78,351	54,069
Other tax credits	42,652	41,381
Depreciation	3,095	3,002
Capital loss carryforward	33,535	8,019
Deferred interest	11,666	7,622
Other	15,849	14,778
Gross deferred tax assets	476,478	394,781
Valuation allowance	(279,683)	(235,503)	$ (198,200)	$ (177,500)
Total deferred tax assets	196,795	159,278
Acquired intangible assets not deductible	(70,570)	(78,663)
Pension prepayments	(2,093)	(542)
Deferred revenue	(6,214)	(2,039)
U.S taxes on unremitted foreign earnings	(11,440)	(67)
Other	(1,192)	(2,025)
Total deferred tax liabilities	91,509	83,336
Net deferred tax assets	$ 105,286	$ 75,942