Income Taxes (Schedule Of Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Income Tax Disclosure [Abstract]
Net operating loss carryforwards	$ 31,329	$ 143,793
Foreign tax credits	2,201	21,099
Capitalized research and development expense	20,999	13,044
Pension benefits	12,296	12,107
Prepaid expenses	30,614	9,250
Deferred revenue	33,886	59,022
Stock-based compensation	11,622	25,360
Other reserves not currently deductible	13,588	16,905
Amortization of intangible assets	96,841	78,351
Other tax credits	55,760	42,652
Depreciation	4,364	3,095
Capital loss carryforward	33,024	33,535
Deferred interest	13,057	11,666
Other	1,152	6,599
Gross deferred tax assets	360,733	476,478
Valuation allowance	(141,950)	(279,683)	$ (235,500)	$ (198,200)
Total deferred tax assets	218,783	196,795
Acquired intangible assets not deductible	(41,139)	(70,570)
Pension prepayments	(2,362)	(2,093)
Deferred revenue	(6,978)	(6,214)
U.S taxes on unremitted foreign earnings	0	(11,440)
U.S taxes on unremitted foreign earnings	(6,641)	0
Other	(1,686)	(1,192)
Total deferred tax liabilities	58,806	91,509
Net deferred tax assets	$ 159,977	$ 105,286