Taxes - Additional Information (Detail) (USD $)	12 Months Ended					6 Months Ended	12 Months Ended		12 Months Ended			3 Months Ended			12 Months Ended
	Oct. 31, 2012	Oct. 31, 2011	Oct. 31, 2010	Oct. 31, 2010 Increase Net	Oct. 31, 2012 Internal Revenue Service (IRS) Fiscal Years 2010 and 2011	Apr. 30, 2011 Internal Revenue Service (IRS) Fiscal Years 2006 through 2009	Oct. 31, 2012 Taiwan Fiscal Year 2008	Oct. 31, 2012 Hungary Fiscal Year 2006 Through 2008	Oct. 31, 2012 Hungary Fiscal Years 2009 And 2010	Oct. 31, 2012 Hungary Fiscal Years 2009 And 2010 Cash Payment Obligations	Oct. 31, 2012 Hungary Fiscal Years 2009 And 2010 Cash payment	Jul. 31, 2012 Hungary Fiscal Year 2006 Through 2010	Apr. 30, 2012 Hungary Fiscal Year 2006 Through 2010	Jan. 31, 2011 Synplicity, Inc.	Oct. 31, 2010 Avant! Corporation
Taxes [Line Items]
Increase in valuation allowance	$ 12,900,000
Unrecognized deferred tax assets	48,200,000
Undistributed foreign earnings	615,200,000
Tax on deferred undistributed foreign earnings	135,800,000
Decrease in gross unrecognized tax benefits	68,200,000
Gross unrecognized tax benefits	109,680,000	177,893,000	213,923,000
Unrecognized tax benefits affecting effective tax rate	75,300,000	177,500,000
The sum of the amounts of estimated penalties and interest recognized in the period arising from income tax examinations	(5,800,000)	2,800,000	3,400,000
The amount of estimated penalties and interest accrued as of the balance sheet date arising from income tax examinations	600,000	7,400,000
Estimated potential decrease in underlying unrecognized tax benefits, minimum	0
Estimated potential decrease in underlying unrecognized tax benefits, maximum	16,000,000
Decrease in unrecognized tax benefits resulting from settlement with taxing authorities	80,137,000	1,258,000			24,700,000	35,900,000	16,500,000					24,200,000	27,000,000	4,000,000	67,800,000
Tax impact from tax settlements					15,900,000	32,800,000	14,700,000		6,300,000						94,300,000
Release of valuation allowance															21,600,000
Tax adjustments settlements and unusual provisions			72,300,000	55,400,000
Decrease in deferred tax assets due to utilization of foreign tax credit carryover net of reversal of valuation allowance			25,200,000
Cash payments as a result of settlement								$ 5,100,000		$ 3,200,000	$ 10,900,000