Income Taxes (Narrative) (Details) (USD $)	3 Months Ended		12 Months Ended
	Sep. 30, 2012	Sep. 30, 2010	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2009
Income Tax Disclosure [Line Items]
Statutory federal income tax rate			35.00%	35.00%	35.00%
Charge to the income tax provision related to the establishment of a valuation allowance on U.S. net deferred tax assets			$ 124,500,000
Effect of change in the tax status of the foreign legal entity			4,200,000
Effective income tax rate, one-time increase			3.00%	1.00%	53.00%
Tax benefit related to research and development				2,300,000
Net increase provision for income tax benefit				1,500,000
Income tax effect on reorganization, tax provision				43,400,000
Tax provision related to research and development cost sharing prepayment			7,800,000	7,500,000	6,000,000
Prepaid income taxes	700,000		700,000	0
Income taxes payable	16,400,000		16,400,000	27,500,000
Accrued income taxes	800,000		800,000	11,900,000
Other current liabilities	4,400,000		4,400,000	5,400,000
Other liabilities	11,200,000		11,200,000	10,200,000
Income tax payments			53,000,000	28,100,000	34,300,000
Net deferred tax assets	11,283,000		11,283,000	121,856,000
Establish valuation allowance in the U.S. on foreign tax credits	124,500,000		124,500,000	0	4,800,000
Net operating loss carryforwards	2,900,000		2,900,000
Valuation allowance	170,404,000		170,404,000	38,600,000
Interest expense			300,000	300,000	500,000
Penalty expense			100,000	0	100,000
Interest expense related to income tax accruals	2,300,000		2,300,000	2,000,000
Accrued tax penalties	100,000		100,000
Unrecognized tax benefit	19,100,000	15,900,000	19,100,000	16,200,000	15,900,000	16,900,000
Unrecognized tax benefits, net of tax	19,100,000		19,100,000	15,900,000
Income tax provision upon recognition of unrecognized tax benefit	18,300,000		18,300,000
Unrecognized tax benefits, increase in valuation allowance upon recognition	5,300,000		5,300,000
Potential decrease in unrecognized tax benefits	6,000,000		6,000,000
Stock-based compensation			51,305,000	45,402,000	48,911,000
Tax benefit recognition related to stock based compensation			2,800,000	13,600,000	14,800,000
Increase (decrease) in income taxes payable			4,005,000	(18,931,000)	5,864,000
Income tax charge (reversal) on undistributed earnings of foreign subsidiaries		43,400,000		6,500,000
Foreign currency translation adjustment in accumulated comprehensive income		700,000
Undistributed earnings of subsidiaries	209,000,000		209,000,000	99,000,000
Massachusetts Research And Development [Member]
Income Tax Disclosure [Line Items]
Research and development credit carryforwards, expiration dates			beginning in 2016 and ending in 2027
Credit carryforwards	18,300,000		18,300,000
Foreign Country [Member]
Income Tax Disclosure [Line Items]
Net operating loss carryforwards	110,300,000		110,300,000
Valuation allowance	23,300,000		23,300,000
Japan [Member]
Income Tax Disclosure [Line Items]
Impact of a Japanese legislative change on our Japan entities' deferred tax assets			1,400,000
Windfall Tax Benefit [Member]
Income Tax Disclosure [Line Items]
Increase (decrease) in income taxes payable			1,100,000	9,400,000	(1,100,000)
Windfall tax deductions not yet recognized	18,000,000		18,000,000
Realignment Of European Business [Member]
Income Tax Disclosure [Line Items]
Deferred charges	7,700,000		7,700,000	11,400,000
Other current assets	3,600,000		3,600,000	3,600,000
Other assets			4,100,000	7,800,000
Domestic Country [Member]
Income Tax Disclosure [Line Items]
Business reorganization taxable gains				46,400,000	446,000,000
Deferred tax liabilities, available for offset against deferred tax assets	28,000,000		28,000,000
Deferred tax liabilities, unavailable for offset against deferred tax assets	6,100,000		6,100,000
Valuation allowance	147,100,000		147,100,000
Intercompany loan receivable from foreign subsidiary	280,700,000		280,700,000
CoCreate [Member]
Income Tax Disclosure [Line Items]
Net operating loss carryforwards	1,100,000		1,100,000
Operating loss carryforwards, expiration dates			2019 through 2027
MKS [Member]
Income Tax Disclosure [Line Items]
Net operating loss carryforwards	1,000,000		1,000,000
Operating loss carryforwards, expiration dates			2020 through 2030
4CS [Member]
Income Tax Disclosure [Line Items]
Net operating loss carryforwards	$ 700,000		$ 700,000
Operating loss carryforwards, expiration dates			2030