Mentor Graphics (MENT) 10-K 17 Mar 14 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
	Jan. 31, 2014	Mar. 13, 2014	Jul. 31, 2013
Document Type	'10-K	'	'
Amendment Flag	'false	'	'
Document Period End Date	31-Jan-14	'	'
Document Fiscal Year Focus	'2014	'	'
Document Fiscal Period Focus	'FY	'	'
Trading Symbol	'MENT	'	'
Entity Registrant Name	'MENTOR GRAPHICS CORP	'	'
Entity Central Index Key	'0000701811	'	'
Current Fiscal Year End Date	'--01-31	'	'
Entity Filer Category	'Large Accelerated Filer	'	'
Entity Common Stock, Shares Outstanding	'	115,360,422	'
Entity Well-known Seasoned Issuer	'Yes	'	'
Entity Voluntary Filers	'No	'	'
Entity Current Reporting Status	'Yes	'	'
Entity Public Float	'	'	$2,313,193,631

Consolidated_Statements_of_Inc

Consolidated Statements of Income (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Revenues:	'	'	'
System and software	$737,790	$681,881	$631,549
Service and support	418,583	406,846	383,089
Total revenues	1,156,373	1,088,727	1,014,638
Cost of revenues:	'	'	'
System and software	65,288	64,280	54,972
Service and support	118,221	117,609	108,690
Amortization of purchased technology	3,598	7,801	9,796
Total cost of revenues	187,107	189,690	173,458
Gross profit	969,266	899,037	841,180
Operating expenses:	'	'	'
Research and development	348,817	313,962	310,758
Marketing and selling	342,799	338,653	326,608
General and administration	75,543	70,692	74,811
Equity in earnings of Frontline	-4,092	-1,764	-2,268
Amortization of intangible assets	6,230	5,915	5,905
Special charges	16,929	9,946	13,174
Total operating expenses	786,226	737,404	728,988
Operating income	183,040	161,633	112,192
Other (expense) income, net	-520	-1,432	1,576
Interest expense	-19,452	-18,866	-31,444
Income before income tax	163,068	141,335	82,324
Income tax expense (benefit)	9,510	2,701	-1,063
Net income	153,558	138,634	83,387
Less: Loss attributable to noncontrolling interest	-1,700	-102	-485
Net income attributable to Mentor Graphics shareholders	$155,258	$138,736	$83,872
Net income per share:	'	'	'
Basic (in dollars per share)	$1.33	$1.20	$0.76
Diluted (in dollars per share)	$1.29	$1.17	$0.74
Weighted average number of shares outstanding:	'	'	'
Basic (in shares)	113,671	110,998	110,138
Diluted (in shares)	116,702	114,017	112,915
Cash dividends declared per common share	$0.18	$0	$0

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Net income	$153,558	$138,634	$83,387
Other comprehensive loss, net of tax:	'	'	'
Change in unrealized gain (loss) on derivative instruments	1,653	829	-402
Cash flow hedge reclassification adjustment for net gain (loss) included in net income	1,599	636	-199
Cash flow hedges change net of tax expense (benefit)	54	193	-203
Less: reclassification adjustment for net gain (loss) included in net income	-6,790	-3,110	-3,149
Change in pension liability, net of tax expense (benefit)	135	-420	212
Other comprehensive loss	-6,601	-3,337	-3,140
Comprehensive income	146,957	135,297	80,247
Net income (loss) attributable to noncontrolling interest	-1,700	-102	-485
Change in accumulated translation adjustment attributable to noncontrolling interest	-5	-56	-127
Comprehensive loss attributable to the noncontrolling interest	-1,705	-158	-612
Comprehensive income attributable to Mentor Graphics shareholders	$148,662	$135,455	$80,859

Consolidated_Statements_of_Com1

Consolidated Statements of Comprehensive Income Consolidated Statements of Comprehensive Income (Parenthetical) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Statement of Comprehensive Income [Abstract]	'	'	'
Other comprehensive income (loss), derivatives qualifying as hedges, tax	$0	$1	($73)
Other comprehensive income (loss), pension and other postretirement benefit plans, tax	$72	($284)	$110

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Jan. 31, 2014	Jan. 31, 2013
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$293,322	$223,783
Short-term investments	3,990	0
Trade accounts receivable, net of allowance for doubtful accounts of $5,469 as of January 31, 2014 and $5,331 as of January 31, 2013	454,483	412,245
Other receivables	15,506	10,974
Inventory	25,121	18,036
Prepaid expenses and other	24,031	24,941
Deferred income taxes	13,656	14,973
Total current assets	830,109	704,952
Property, plant, and equipment, net	160,165	162,402
Term receivables	270,365	250,497
Goodwill	549,044	535,932
Intangible assets, net	22,799	21,838
Other assets	71,627	69,663
Total assets	1,904,109	1,745,284
Current liabilities:	'	'
Short-term borrowings	9,590	5,964
Accounts payable	21,548	20,906
Income taxes payable	3,365	9,180
Accrued payroll and related liabilities	102,848	101,354
Accrued and other liabilities	42,457	40,662
Deferred revenue	231,179	233,759
Total current liabilities	410,987	411,825
Notes payable	224,261	218,546
Deferred revenue	17,398	17,755
Income tax liability	18,431	22,663
Other long-term liabilities	32,259	28,318
Total liabilities	703,336	699,107
Commitments and contingencies (Note 8)	'	'
Noncontrolling interest with redemption feature	15,479	12,698
Stockholders' equity:	'	'
Common stock, no par value, 300,000 shares authorized as of January 31, 2014 and January 31, 2013; 115,722 shares issued and outstanding as of January 31, 2014 and 112,902 shares issued and outstanding as of January 31, 2013	838,939	810,902
Retained earnings	327,552	197,178
Accumulated other comprehensive income	18,803	25,399
Total stockholders' equity	1,185,294	1,033,479
Total liabilities and stockholders' equity	$1,904,109	$1,745,284

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Jan. 31, 2014	Jan. 31, 2013
In Thousands, unless otherwise specified
Allowance for doubtful accounts receivable, current	$5,469	$5,331
Common stock, no par value	$0	$0
Common stock, shares authorized	300,000	300,000
Common stock, shares issued	115,722	112,902
Common stock, shares outstanding	115,722	112,902

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Operating Cash Flows:	'	'	'
Net income	$153,558	$138,634	$83,387
Adjustments to reconcile net income to net cash provided by operating activities:	'	'	'
Depreciation of property, plant, and equipment	34,563	33,305	31,948
Amortization of intangible assets, debt costs and other	17,891	20,246	22,239
Loss on debt extinguishment	0	0	3,518
Write-off of debt discount and debt issuance costs	0	0	8,010
Stock-based compensation	29,350	23,697	21,658
Deferred income taxes	8,550	-1,634	2,754
Changes in other long-term liabilities	-3,708	-6,143	2,889
Gain on converstion of equity method investment to controlling interest	0	0	-1,519
Dividends received from unconsolidated entities, net of equity in income	1,290	4,358	4,874
Other	-11	74	-7
Changes in operating assets and liabilities, net of effect of acquired businesses:	'	'	'
Trade accounts receivable, net	-43,811	-58,389	-8,915
Prepaid expenses and other	-17,774	-21,861	-16,295
Term receivables, long-term	-21,285	-30,980	-54,637
Accounts payable and accrued liabilities	4,473	-2,720	-3,122
Income taxes receivable and payable	-10,487	-5,084	-11,725
Deferred revenue	-2,896	45,784	18,881
Net cash provided by operating activities	149,703	139,287	103,938
Investing Cash Flows:	'	'	'
Proceeds from the sales and maturities of short-term investments	3,112	0	0
Purchases of short-term investments	7,820	0	0
Increase in restricted cash	0	0	-3,977
Purchases of property, plant, and equipment	-30,761	-45,130	-41,555
Acquisitions of business and equity interests and other intangible assets, net of cash acquired	-20,906	-15,652	-15,260
Net cash used in investing activities	-56,375	-60,782	-60,792
Financing Cash Flows:	'	'	'
Proceeds from issuance of common stock	53,013	46,756	37,460
Repurchase of common stock	-49,995	-33,914	-89,996
Tax benefit from share options exercised	386	266	0
Dividends paid	-20,398	0	0
Net increase (decrease) in short-term borrowing	3,748	-8,149	-1,284
Debt and equity issuance costs	0	0	9,020
Proceeds from notes payable	0	0	253,000
Repayments of notes payable	0	0	-219,919
Repayments of other borrowings	-7,762	-3,016	0
Net cash (used in) provided by financing activities	-21,008	1,943	-29,759
Effect of exchange rate changes on cash and cash equivalents	-2,781	-3,164	-1
Net change in cash and cash equivalents	69,539	77,284	13,386
Cash and cash equivalents at the beginning of the period	223,783	146,499	133,113
Cash and cash equivalents at the end of the period	$293,322	$223,783	$146,499

Consolidated_Statement_of_Stoc

Consolidated Statement of Stockholders Equity (USD $)	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Stockholders' Equity, Total	Noncontrolling Interest
In Thousands	USD ($)		USD ($)	USD ($)	USD ($)	USD ($)	USD ($)
Stockholders' equity at Jan. 31, 2011	'	'	$765,179	($20,158)	$31,693	$776,714	'
Common stock, shares outstanding at Jan. 31, 2011	'	111,249	'	'	'	'	'
Net income attributable to Mentor Graphics shareholders	83,872	'	'	83,872	'	83,872	'
Net income (loss) attributable to noncontrolling interest	-485	'	'	'	'	'	-485
Other comprehensive loss	'	'	'	'	-3,013	-3,013	'
Change in accumulated translation adjustment attributable to noncontrolling interest	-127	'	'	'	'	'	-127
Convertible debt feature	'	'	42,531	'	'	42,531	'
Acquisition of controlling interest	'	'	-815	'	'	-815	8,196
Adjustment of noncontrolling interest to redemption value	'	'	'	-1,682	'	-1,682	1,682
Stock issued under stock awards and stock purchase plans, shares	'	4,945	'	'	'	'	'
Stock issued under stock awards and stock purchase plans, amount	'	'	37,460	'	'	37,460	'
Stock repurchased, shares	'	-6,805	'	'	'	'	'
Stock repurchased, amount	'	'	-89,996	'	'	-89,996	'
Stock compensation expense	'	'	21,516	'	'	21,516	'
Stock withheld for taxes, shares	'	-43	'	'	'	'	'
Stock withheld for taxes, amount	'	'	-513	'	'	-513	'
Noncontrolling interest with redemption feature	'	'	'	'	'	'	9,266
Stockholders' equity at Jan. 31, 2012	'	'	775,362	62,032	28,680	866,074	'
Common stock, shares outstanding at Jan. 31, 2012	'	109,346	'	'	'	'	'
Net income attributable to Mentor Graphics shareholders	138,736	'	'	138,736	'	138,736	'
Net income (loss) attributable to noncontrolling interest	-102	'	'	'	'	'	-102
Other comprehensive loss	'	'	'	'	-3,281	-3,281	'
Change in accumulated translation adjustment attributable to noncontrolling interest	-56	'	'	'	'	'	-56
Adjustment of noncontrolling interest to redemption value	'	'	'	-3,590	'	-3,590	3,590
Stock issued under stock awards and stock purchase plans, shares	'	5,875	'	'	'	'	'
Stock issued under stock awards and stock purchase plans, amount	'	'	46,756	'	'	46,756	'
Stock repurchased, shares	'	-2,245	'	'	'	'	'
Stock repurchased, amount	'	'	-33,914	'	'	-33,914	'
Stock compensation expense	'	'	23,697	'	'	23,697	'
Stock withheld for taxes, shares	'	-74	'	'	'	'	'
Stock withheld for taxes, amount	'	'	-1,265	'	'	-1,265	'
Tax benefit associated with the exercise of stock options	'	'	266	'	'	266	'
Noncontrolling interest with redemption feature	12,698	'	'	'	'	'	12,698
Stockholders' equity at Jan. 31, 2013	'	'	810,902	197,178	25,399	1,033,479	'
Common stock, shares outstanding at Jan. 31, 2013	112,902	112,902	'	'	'	'	'
Net income attributable to Mentor Graphics shareholders	155,258	'	'	155,258	'	155,258	'
Net income (loss) attributable to noncontrolling interest	-1,700	'	'	'	'	'	-1,700
Other comprehensive loss	'	'	'	'	-6,596	-6,596	'
Change in accumulated translation adjustment attributable to noncontrolling interest	-5	'	'	'	'	'	-5
Adjustment of noncontrolling interest to redemption value	'	'	'	-4,486	'	-4,486	4,486
Dividends	'	'	'	-20,398	'	-20,398	'
Stock issued under stock awards and stock purchase plans, shares	'	5,618	'	'	'	'	'
Stock issued under stock awards and stock purchase plans, amount	'	'	53,013	'	'	53,013	'
Stock repurchased, shares	'	-2,593	'	'	'	'	'
Stock repurchased, amount	'	'	-49,995	'	'	-49,995	'
Stock compensation expense	'	'	29,350	'	'	29,350	'
Stock withheld for taxes, shares	'	-205	'	'	'	'	'
Stock withheld for taxes, amount	'	'	-4,717	'	'	-4,717	'
Tax benefit associated with the exercise of stock options	'	'	386	'	'	386	'
Noncontrolling interest with redemption feature	15,479	'	'	'	'	'	15,479
Stockholders' equity at Jan. 31, 2014	'	'	$838,939	$327,552	$18,803	$1,185,294	'
Common stock, shares outstanding at Jan. 31, 2014	115,722	115,722	'	'	'	'	'

Nature_of_Operations

Nature of Operations	12 Months Ended
	Jan. 31, 2014
Nature of Operations	'
	Nature of Operations
	We are a supplier of electronic design automation systems — advanced computer software and emulation hardware systems used to automate the design, analysis, and testing of complex electro-mechanical systems, electronic hardware, and embedded systems software in electronic systems and components. We market our products and services worldwide, primarily to large companies in the communications, computer, consumer electronics, semiconductor, networking, multimedia, military and aerospace, and transportation industries. We sell and license our products through our direct sales force and a channel of distributors and sales representatives. We were incorporated in Oregon in 1981 and our common stock is traded on The NASDAQ Global Select Market under the symbol “MENT.” In addition to our corporate offices in Wilsonville, Oregon, we have sales, support, software development, and professional service offices worldwide.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	12 Months Ended
	Jan. 31, 2014
Accounting Policies [Abstract]	'
Summary of Significant Accounting Policies	'
	Summary of Significant Accounting Policies
	Principles of Consolidation
	The consolidated financial statements include our financial statements and those of our wholly-owned and majority-owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation.
	We do not have off-balance sheet arrangements, financings, or other similar relationships with unconsolidated entities or other persons, also known as special purpose entities. In the ordinary course of business, we lease certain real properties, primarily field sales offices, research and development facilities, and equipment, as described in Note 8. “Commitments and Contingencies.”
	Foreign Currency Translation
	Local currencies are the functional currencies for our foreign subsidiaries except for certain subsidiaries in Ireland, Singapore, Egypt, and the Netherlands Antilles where the United States (U.S.) dollar is used as the functional currency. We translate assets and liabilities of foreign operations, excluding certain subsidiaries in Ireland, Singapore, Egypt, and the Netherlands Antilles to U.S. dollars at current rates of exchange and revenues and expenses using weighted average rates. We include foreign currency translation adjustments in stockholders’ equity as a component of accumulated other comprehensive income. We maintain the accounting records for certain subsidiaries in Ireland, Singapore, Egypt, and the Netherlands Antilles in the U.S. dollar and accordingly no translation is necessary. We include foreign currency transaction gains and losses as a component of other income (expense), net.
	Use of Estimates
	U.S. generally accepted accounting principles require management to make estimates and assumptions that affect the reported amount of assets, liabilities, and contingencies at the date of the financial statements and the reported amounts of revenues and expenses during the reporting periods. Such estimates include valuation of accounts receivable, revenue recognition, business combinations, income taxes, goodwill, intangible assets, long-lived assets, special charges, and stock-based compensation. These estimates and assumptions are based on our best judgment. We evaluate our estimates and assumptions on an ongoing basis using historical experience and other factors, including the current economic environment, which we believe to be reasonable under the circumstances. We adjust estimates and assumptions as facts and circumstances dictate. Actual results could differ from these estimates. Any changes in estimates will be reflected in the financial statements in future periods.
	Investments
	We classify investments with original maturities of 90 days or less as cash equivalents. Short-term investments include certificates of deposit with original maturities in excess of 90 days and less than one year at the time of purchase.
	Long-term investments, included in other assets on the accompanying consolidated balance sheets, include investments with maturities in excess of one year from the balance sheet date and equity securities. We determine the appropriate classification of our investments at the time of purchase. For investments in equity securities, we use the equity method of accounting when our investment gives us the ability to exercise significant influence over the operating and financial policies of the investee. Under the equity method, we currently record our share of earnings or losses as a component of other income (expense), net, equal to our proportionate share of the earnings or losses of the investee. For investments in equity securities of private companies without a readily determinable fair value, and as to which we do not exercise significant influence over the investee, we record our investment under the cost method of accounting. Under the cost method of accounting, we carry the investment at historical cost. We periodically evaluate the fair value of all investments to determine if an other-than-temporary decline in value has occurred.
	Investment in Frontline
	We have a 50% interest in a joint venture, Frontline P.C.B. Solutions Limited Partnership (Frontline), a provider of engineering software solutions for the printed circuit board industry. We use the equity method of accounting for Frontline, which results in reporting our investment as one line within other assets in the consolidated balance sheet and our share of earnings on one line in the consolidated statement of income. Frontline reports on a calendar year basis. As such, we record our interest in the earnings of Frontline on a one-month lag.
	Although we do not exert control, we actively participate in regular and periodic activities with respect to Frontline such as budgeting, business planning, marketing, and direction of research and development projects. Accordingly, we have included our interest in the earnings of Frontline as a component of operating income.
	Property, Plant, and Equipment, Net
	We state property, plant, and equipment at cost and capitalize expenditures for additions to property, plant, and equipment. We expense maintenance and repairs which do not improve or extend the life of the respective asset as incurred. We compute depreciation on a straight-line basis as follows:
		Estimated Useful Lives (in years)
	Buildings		40
	Land improvements		20
	Computer equipment and furniture	3	-	5
	Leasehold improvements(1)	3	-	10
	(1)    Amortized over the shorter of the lease term or estimated life.
	A summary of property, plant, and equipment, net is as follows:
	As of January 31,	2014			2013
	Computer equipment and furniture	$	319,698		$	308,229
	Buildings and building equipment	101,073			97,989
	Land and improvements	21,321			21,345
	Leasehold improvements	38,900			35,753
	Property, plant, and equipment, gross	480,992			463,316
	Less: accumulated depreciation and amortization	(320,827		)	(300,914		)
	Property, plant, and equipment, net	$	160,165		$	162,402
	Goodwill and Intangible Assets
	Goodwill represents the excess of the aggregate purchase price over the fair value of the net tangible assets and other intangible assets acquired in our business combinations. Intangible assets, net primarily includes purchased technology, in-process research and development, backlog, tradename, and customer relationships acquired in our business combinations. We review long-lived assets, including intangible assets with definite lives, for impairment whenever events or changes in circumstances indicate the carrying amount of such assets may not be recoverable. We assess the recoverability of our long-lived assets by determining whether the carrying values of the asset groups are greater than the forecasted undiscounted net cash flows of the related asset group. If we determine the assets are impaired, we write down the assets to their estimated fair value. We determine fair value based on forecasted discounted net cash flows or appraised values, depending upon the nature of the assets. In the event we determine our long-lived assets have been impaired, we would make an adjustment that would result in a charge for the write-down in the period that the determination was made.
	Goodwill is not amortized, but is tested for impairment at least annually and as necessary if changes in facts and circumstances indicate that the fair value of our reporting unit may be less than the carrying amount. We operate as a single reporting unit for purposes of goodwill evaluation. We completed our annual goodwill impairment test as of January 31, 2014, 2013, and 2012. For purposes of assessing the impairment of goodwill, we estimated the fair value of our reporting unit using its market capitalization as the best evidence of fair value and then compared the fair value to the carrying value of our reporting unit. Our reporting unit passed this step of the goodwill analysis. There were no indicators of impairment to goodwill during fiscal 2014, 2013, and 2012 and accordingly, no impairment charges were recognized during these fiscal periods.
	We amortize purchased technology over three to five years to system and software cost of revenues and other intangible asset costs over one to five years to operating expenses. We amortize capitalized in-process research and development (resulting from acquisitions), upon completion of projects to cost of revenues over the estimated useful life of the technology. Alternatively, if we abandon a project, in-process research and development costs are expensed to operating expense when that determination is made.
	Total purchased technology and other intangible asset amortization expenses were as follows:
	Year ended January 31,	2014			2013			2012
	Purchased technology and other intangible asset amortization expenses	$	9,828		$	13,716		$	15,701
	As of January 31, 2014, the carrying value of goodwill and intangible assets was as follows:
	As of January 31,	2014			2013
	Goodwill	$	549,044		$	535,932
	Net purchased technology and in-process research and development(1)	$	11,210		$	8,019
	Net other intangible assets(2)	$	11,589		$	13,819
	(1)Includes accumulated amortization of $124,536 as of January 31, 2014 and $121,011 as of January 31, 2013.
	(2)Includes accumulated amortization of $71,216 as of January 31, 2014 and $65,049 as of January 31, 2013.
	The following table summarizes goodwill activity:
	Balance as of January 31, 2012	$	527,102
	Acquisitions	8,437
	Earnouts	370
	Foreign exchange	23
	Balance as of January 31, 2013	$	535,932
	Acquisitions	12,545
	Earnouts	288
	Foreign exchange	279
	Balance as of January 31, 2014	$	549,044
	We estimate the aggregate amortization expense related to purchased technology and other intangible assets will be as follows:
	Fiscal years ending January 31,
	2015	$	9,402
	2016	6,516
	2017	3,401
	2018	2,361
	2019	1,071
	Thereafter	48
Aggregate amortization expense	$	22,799
Noncontrolling Interest with Redemption Feature
As of January 31, 2014, our balance sheet includes a noncontrolling interest resulting from a business combination in which we acquired majority ownership in a privately-held company. In conjunction with this business combination, we also entered into an agreement which provides us a call option to acquire the noncontrolling interest and the noncontrolling interest holders a put option to sell their interests to us for prices based on formulas defined in the agreement. The noncontrolling interest adjusted for this redemption feature based on the put option price formula, is presented on the consolidated balance sheet under the caption “Noncontrolling interest with redemption feature.” Because the redemption of the noncontrolling interest is outside of our control, we have presented this interest outside of stockholders’ equity.
The noncontrolling interest with redemption feature is recognized at the greater of:
i. The calculated redemption put value as of the balance sheet date; or
ii. The initial noncontrolling interest value adjusted for the noncontrolling interest holders' share of:
a. cumulative impact of net income (loss); and
b. other changes in accumulated other comprehensive income.
Increases (or decreases to the extent they offset previous increases) in the calculated redemption feature put value are recorded directly to retained earnings as if the balance sheet date were also the redemption date. Changes in the redemption feature put value, to the extent they are significant, also result in an adjustment to net income attributable to shareholders in the calculation of basic and diluted net income per share.
The results of the majority-owned subsidiary are presented in our consolidated results with an adjustment reflected on the face of our statement of income and the face of our statement of comprehensive income for the noncontrolling investors' interest in the results of the subsidiary.
Income Taxes
We use the asset and liability method of accounting for income taxes. Under this method, we recognize deferred income taxes for the future tax consequences attributable to temporary differences between the financial statement carrying amounts and tax balances of existing assets and liabilities. We calculate deferred tax assets and liabilities using enacted laws and tax rates that will be in effect when we expect the differences to reverse and be applied to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred taxes of a change in tax rates is recognized in income in the period that includes the enactment date. Deferred tax assets are recognized for deductible temporary differences, net operating loss carryforwards, and credit carryforwards if it is more likely than not that the tax benefits will be realized. Deferred tax assets are not recorded, however, in the following circumstances:
•	A deferred tax asset is not recorded for net operating loss carryforwards created by excess tax benefits from the exercise of stock options. To the extent such net operating loss carryforwards are utilized, we will increase stockholders’ equity. The historical and current deferred tax assets related to excess tax benefits from stock option exercises are excluded in the presentation of our financial results.
•	Deferred tax assets are not recorded to the extent they are attributed to uncertain tax positions.
For deferred tax assets that cannot be recognized under the more-likely-than-not-standard, we have established a valuation allowance. In the event we determine that we are able to realize our deferred tax assets in the future in excess of our net recorded amount, we would reverse the valuation allowance associated with such deferred tax assets in the period such determination was made. Also, if we determine that we are not able to realize all or part of our net deferred tax assets in the future, we would record a valuation allowance on such net deferred tax assets with a corresponding increase in expense in the period such determination was made.
We are subject to income taxes in the U.S. and in numerous foreign jurisdictions, and in the ordinary course of business, there are many transactions and calculations where the ultimate tax determination is uncertain. While we believe the positions we have taken are appropriate, we have reserves for taxes to address potential exposures involving tax positions that are being challenged or that could be challenged by the tax authorities. We record a benefit on a tax position when we determine that it is more likely than not that the position is sustainable upon examination, including resolution of any related appeals or litigation processes, based on the technical merits of the position. For tax positions that are more likely than not to be sustained, we measure the tax position at the largest amount of benefit that has a greater than 50 percent likelihood of being realized when it is effectively settled. We review the tax reserves as circumstances warrant and adjust the reserves as events occur that affect our potential liability for additional taxes.
Business Combinations
For each business we acquire, the excess of the fair value of the consideration transferred over the fair value of the net tangible assets acquired and net tangible liabilities assumed was allocated to various identifiable intangible assets and goodwill. Identifiable intangible assets typically consist of purchased technology and customer-related intangibles, which are amortized to expense over their useful lives. Goodwill, representing the excess of the purchase consideration over the fair value of net tangible and identifiable intangible assets, is not amortized.
Acquisitions for the year ended January 31, 2014 consisted of 4 privately-held companies, all of which were accounted for as business combinations. These acquisitions were not material individually or in the aggregate.
Derivative Financial Instruments
We are exposed to fluctuations in foreign currency exchange rates and have established a foreign currency hedging program to hedge certain foreign currency forecasted transactions and exposures from existing assets and liabilities. Our derivative instruments consist of foreign currency exchange contracts. By using derivative instruments, we subject ourselves to credit risk. If a counterparty fails to fulfill its performance obligations under a derivative contract, our credit risk will equal the fair value of the derivative instrument. Generally, when the fair value of our derivative contracts is a net asset, the counterparty owes us, thus creating a receivable risk. We minimize counterparty credit risk by entering into derivative transactions with major financial institutions and, as such, we do not expect material losses as a result of default by our counterparties. We execute foreign currency transactions in exchange-traded or over-the-counter markets for which quoted prices exist. We do not hold or issue derivative financial instruments for speculative or trading purposes.
To manage the foreign currency volatility, we aggregate exposures on a consolidated basis to take advantage of natural offsets. The primary exposures are the Japanese yen, where we are in a long position, and the euro and the British pound, where we are in a short position. Most large European revenue contracts are denominated and paid to us in U.S. dollars while our European expenses, including substantial research and development operations, are paid in local currencies causing a short position in the euro and the British pound. In addition, we experience greater inflows than outflows of Japanese yen as almost all Japanese-based customers contract and pay us in Japanese yen. While these exposures are aggregated on a consolidated basis to take advantage of natural offsets, substantial exposures remain.
To partially offset the net exposures in the euro, British pound, and the Japanese yen, we enter into foreign currency exchange contracts of less than one year which are designated as cash flow hedges. Any gain or loss on Japanese yen contracts is classified as product revenue when the hedged transaction occurs while any gain or loss on euro and British pound contracts is classified as operating expense when the hedged transaction occurs.
We use an income approach to determine the fair value of our foreign currency contracts and record them at fair value utilizing observable market inputs at the measurement date. We report the fair value of derivatives in other receivables, if the balance is an asset, or accrued liabilities, if the balance is a liability, in the consolidated balance sheet. The accounting for changes in the fair value of a derivative depends upon whether it has been designated in a hedging relationship and on the type of hedging relationship. To qualify for designation in a hedging relationship, specific criteria must be met and the appropriate documentation maintained. Hedging relationships, if designated, are established pursuant to our risk management policy and are initially and regularly evaluated to determine whether they are expected to be, and have been, highly effective hedges. We formally document all relationships between foreign currency exchange contracts and hedged items as well as our risk management objectives and strategies for undertaking various hedge transactions.
All hedges designated as cash flow hedges are linked to forecasted transactions and we assess, both at inception of the hedge and on an ongoing basis, the effectiveness of the foreign currency exchange contracts in offsetting changes in the cash flows of the hedged items. We report the effective portions of the net gains or losses on these foreign currency exchange contracts as a component of accumulated other comprehensive income in stockholders’ equity. Accumulated other comprehensive income associated with hedges of forecasted transactions is reclassified to the consolidated statement of income in the same period the forecasted transaction occurs or the hedge is no longer effective. We expect substantially all of the hedge balance in accumulated other comprehensive income to be reclassified to the consolidated statement of income within the next twelve months.
We enter into foreign currency exchange contracts to offset the earnings impact relating to the variability in exchange rates on certain short-term monetary assets and liabilities denominated in non-functional currencies. We do not designate these foreign currency contracts as hedges. The change in fair value of these derivative instruments not designated as hedging instruments is reported each period in other income (expense), net, in our consolidated statement of income.
Revenue Recognition
We report revenue in two categories based on how revenue is generated: (i) system and software and (ii) service and support.
System and software revenues – We derive system and software revenues from the sale of licenses of software products, emulation hardware systems, and finance fee revenues from our long-term installment receivables resulting from product sales. We primarily license our products using two different license types:
1.Term licenses – We use this license type primarily for software sales. This license type provides the customer with the right to use a fixed list of software products for a specified time period, typically three years, with payments spread over the license term, and does not provide the customer with the right to use the products after the end of the term. Term license arrangements may allow the customer to share products between multiple locations and remix product usage from the fixed list of products at regular intervals during the license term. We generally recognize product revenue from term license arrangements upon product delivery and start of the license term. In a term license agreement where we provide the customer with rights to unspecified or unreleased future products, we recognize revenue ratably over the license term.
2.Perpetual licenses – We use this license type for software and emulation hardware system sales. This license type provides the customer with the right to use the product in perpetuity and typically does not provide for extended payment terms. We generally recognize product revenue from perpetual license arrangements upon product delivery assuming all other criteria for revenue recognition have been met.
We include finance fee revenues from the accretion of the discount on long-term installment receivables in system and software revenues. Finance fee revenues were approximately 2.0% of total revenues for fiscal 2014, 2013, and 2012.
Service and support revenues – We derive service and support revenues from software and hardware post-contract maintenance or support services and professional services, which include consulting, training, and other services. We recognize revenue ratably over the support services term. We record professional service revenue as the services are provided to the customer.
We determine whether product revenue recognition is appropriate based upon the evaluation of whether the following four criteria have been met:
1.Persuasive evidence of an arrangement exists – Generally, we use either a customer signed contract or qualified customer purchase order as evidence of an arrangement for both term and perpetual licenses. For professional service engagements, we generally use a signed professional services agreement and a statement of work to evidence an arrangement. Sales through our distributors are evidenced by an agreement governing the relationship, together with binding purchase orders from the distributor on a transaction-by-transaction basis.
2.Delivery has occurred – We generally deliver software and the corresponding access keys to customers electronically. Electronic delivery occurs when we provide the customer access to the software. We may also deliver the software on a compact disc. With respect to emulation hardware systems, we transfer title to the customer upon shipment. Our software license and emulation hardware system agreements generally do not contain conditions for acceptance.
3.Fee is fixed or determinable – We assess whether a fee is fixed or determinable at the outset of the arrangement, primarily based on the payment terms associated with the transaction. We have established a history of collecting under the original contract with installment terms without providing concessions on payments, products, or services. Additionally, for installment contracts, we determine that the fee is fixed or determinable if the arrangement has a payment schedule that is within the term of the licenses and the payments are collected in equal or nearly equal installments, when evaluated on a cumulative basis. If the fee is not deemed to be fixed or determinable, we recognize revenue as payments become due and payable.
Significant judgment is involved in assessing whether a fee is fixed or determinable. We must also make these judgments when assessing whether a contract amendment to a term arrangement (primarily in the context of a license extension or renewal) constitutes a concession. Our experience has been that we are able to determine whether a fee is fixed or determinable for term licenses. If we no longer were to have a history of collecting under the original contract without providing concessions on term licenses, revenue from term licenses would be required to be recognized when payments under the installment contract become due and payable. Such a change could have a material impact on our results of operations.
4.Collectibility is probable – To recognize revenue, we must judge collectibility of the arrangement fees on a customer-by-customer basis pursuant to our credit review process. We typically sell to customers with whom there is a history of successful collection. We evaluate the financial position and a customer’s ability to pay whenever an existing customer purchases new products, renews an existing arrangement, or requests an increase in credit terms. For certain industries for which our products are not considered core to the industry or the industry is generally considered troubled, we impose higher credit standards. If we determine that collectibility is not probable based upon our credit review process or the customer’s payment history, we recognize revenue as payments are received.
Multiple element arrangements involving software licenses – For multiple element arrangements involving software and other software-related deliverables, vendor-specific objective evidence of fair value (VSOE) must exist to allocate the total fee among all delivered and non-essential undelivered elements of the arrangement. If undelivered elements of the arrangement are essential to the functionality of the product, we defer revenue until the essential elements are delivered. If VSOE does not exist for one or more non-essential undelivered elements, we defer revenue until such evidence exists for the undelivered elements, or until all elements are delivered, whichever is earlier. If VSOE of all non-essential undelivered elements exists but VSOE does not exist for one or more delivered elements, we recognize revenue using the residual method. Under the residual method, we defer revenue related to the undelivered elements based upon VSOE and we recognize the remaining portion of the arrangement fee as revenue for the delivered elements, assuming all other criteria for revenue recognition are met.
We base our VSOE for certain elements of an arrangement upon the pricing in comparable transactions when the element is sold separately. We primarily base our VSOE for term and perpetual support services upon customer renewal history where the services are sold separately. We also base VSOE for professional services and installation services for emulation hardware systems upon the price charged when the services are sold separately.
Multiple element arrangements involving hardware – For multiple element arrangements involving our emulation hardware systems, we allocate revenue to each element based on the relative selling price of each deliverable. In order to meet the separation criteria to allocate revenue to each element we must determine the standalone selling price of each element using a hierarchy of evidence.
The authoritative guidance requires that, in the absence of VSOE or third-party evidence (TPE), a company must develop an estimated selling price (ESP). ESP is defined as the price at which the vendor would transact if the deliverable was sold by the vendor regularly on a standalone basis. A company should consider market conditions as well as entity-specific factors when estimating a selling price.We base our ESP for certain elements in arrangements on either costs incurred to manufacture a product plus a reasonable profit margin or standalone sales to similar customers. In determining profit margins, we consider current market conditions, pricing strategies related to the class of customer, and the level of penetration we have with the customer. In other cases, we may have limited sales on a standalone basis to the same or similar customers and/or guaranteed pricing on future purchases of the same item.
Software Development Costs
We capitalize software development costs beginning when a product’s technological feasibility has been established by either completion of a detail program design or completion of a working model of the product and ending when a product is available for general release to customers. The period between the achievement of technological feasibility and the general release of our products has historically been of short duration. As a result, such capitalizable software development costs were insignificant and have been charged to research and development expense in all periods in the accompanying consolidated statements of income.
We capitalized $3,698 of acquired developed technology during fiscal 2014. We did not capitalize any acquired developed technology during fiscal 2013 or 2012.
Advertising Costs
We expense all advertising costs as incurred. Advertising expense is included in marketing and selling expense in the accompanying consolidated statement of income and was as follows:
Year ended January 31,	2014			2013			2012
Advertising expense	$	2,654		$	2,326		$	3,015
Special Charges
We record restructuring charges within special charges in the consolidated statement of income in connection with our plans to better align our cost structure with projected operations in the future. Special charges primarily consist of costs incurred related to certain litigation, employee severance, acquisitions, excess facilities, and asset related charges. See additional discussion in Note 13. "Special Charges."
Net Income Per Share
We compute basic net income per share using the weighted average number of common shares outstanding during the period. We compute diluted net income per share using the weighted average number of common shares and potentially dilutive common shares outstanding during the period. Potentially dilutive common shares consist of restricted stock units, common shares issuable upon exercise of employee stock options, purchase rights from employee stock purchase plans, and common shares issuable upon conversion of the convertible subordinated debentures using the treasury stock method, if dilutive. Net income used to compute basic and diluted net income per share is reduced for the adjustment of the noncontrolling interest with redemption feature to its calculated redemption value at January 31, 2014. See additional discussion in Note 11. “Net Income Per Share.”
Accounting for Stock-Based Compensation
We measure stock-based compensation cost at the grant date, based on the fair value of the award, and recognize the expense on a straight-line basis over the employee’s requisite service period. For options and stock awards that vest fully on any termination of service, there is no requisite service period and consequently we recognize the expense fully in the period in which the award is granted. We present the excess tax benefit from the exercise of stock options when the benefit that was previously recorded as a financing activity in the consolidated statements of cash flows is utilized.
We have elected to compute the timing of excess tax benefits from the exercise of stock options on the “with-and-without” approach. Under this approach, we will not record an excess tax benefit until such time as a cash tax benefit is recognized. Further, we will include the impact of these excess tax benefits in the calculation of indirect tax attributes, such as the research and development credit and the domestic manufacturing deduction. We will compute the pool of excess tax benefits available to offset any future shortfalls in the tax benefits actually realized on exercises of stock options as a single pool for employees and non-employees.
See a further description of how we estimate the fair value of stock options and purchase rights under our employee stock purchase plans (ESPPs) in Note 9. “Employee Stock and Savings Plans and Stockholders' Equity.”
Transfer of Financial Assets
We finance certain software license agreements with customers through the sale, assignment, and transfer of the future payments under those agreements to financing institutions on a non-recourse basis. We retain no interest in the transferred receivable. We record such transfers as sales of the related accounts receivable when we are considered to have surrendered control of such receivables. The gain or loss on the sale of receivables is included in general and administration in operating expenses in our consolidated statement of income. The gain or loss on the sale of receivables consists of two components: (i) the discount on sold receivables, which is the difference between the undiscounted balance of the receivables, and the net proceeds received from the financing institution and (ii) the unaccreted interest on the receivables sold. We impute interest on the receivables based on prevailing market rates and record this as a discount against the receivable.
We sold the following receivables to financing institutions on a non-recourse basis and recognized the following gain on the sale of those receivables:
Year ended January 31,	2014			2013			2012
Trade receivables, short-term	$	11,705		$	9,617		$	13,645
Term receivables, long-term	11,912			11,094			16,662
Total receivables sold	23,617			20,711			30,307
Net proceeds	22,943			20,198			29,146
Discount on sold receivables	(674		)	(513		)	(1,161		)
Unaccreted interest on sold receivables	890			568			1,273
Gain on sale of receivables	$	216		$	55		$	112
Reclassifications
Certain items have been reclassified within operating expenses for fiscal 2013. We have reclassified certain litigation costs out of general and administration into special charges, related to patent litigation involving Emulation and Verification Engineering S.A. and EVE-USA, Inc. (together EVE), Synopsys, Inc. (Synopsys), and us regarding emulation technology. These litigation costs are included in special charges because of their unusual nature due to the significance in variability of timing and amount. These reclassifications had no impact on total operating expenses, operating income, or net income. See further discussion of these lawsuits in Note 8. "Commitments and Contingencies."
The reclassification of our previously issued fiscal 2013 consolidated statement of operations was made to conform to the current period presentation. The amounts have been reclassified as follows:
	Year ended January 31, 2013
	As Originally Reported			As Reclassified
General and administration	$	74,324		$	70,692
Special charges	$	6,314		$	9,946

Fair_Value_Measurement

Fair Value Measurement	12 Months Ended
	Jan. 31, 2014
Fair Value Disclosures [Abstract]	'
Fair Value Measurement	'
	Fair Value Measurement
	The following table presents information about financial assets and liabilities measured at fair value on a recurring basis as of January 31, 2014:
		Fair Value				Level 1		Level 2		Level 3
	Bank certificates of deposit	$	3,990			$	—	$	3,990	$	—
	Contingent consideration	$	(4,571	)		$	—	$	—	$	(4,571	)
	Total	$	(581	)		$	—	$	3,990	$	(4,571	)
	The following table presents information about financial assets and liabilities measured at fair value on a recurring basis as of January 31, 2013:
		Fair Value				Level 1		Level 2		Level 3
	Contingent consideration	$	(6,016	)		$	—	$	—	$	(6,016	)
	The Financial Accounting Standards Board's authoritative guidance for the hierarchy of valuation techniques is based on whether the inputs to those valuation techniques are observable or unobservable. Observable inputs reflect market data obtained from independent sources. Unobservable inputs reflect our market assumptions. The fair value hierarchy consists of the following three levels:
	•	Level 1—Quoted prices for identical instruments in active markets;
	•	Level 2—Quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model-derived valuations whose significant inputs are observable; and
	•	Level 3—One or more significant inputs to the valuation model are unobservable.
	We based the fair value of bank certificates of deposit included in short-term investments on quoted market prices for similar instruments in markets that are not active (Level 2).
	In connection with certain acquisitions, payment of a portion of the purchase price is contingent typically upon the acquired business’ achievement of certain revenue goals. As of January 31, 2014, of the total recorded balance, $1,565 was included in accrued and other liabilities and $3,006 was included in other long-term liabilities on our consolidated balance sheet. As of January 31, 2013, of the total recorded balance, $1,197 was included in accrued and other liabilities and $4,819 was included in other long-term liabilities on our consolidated balance sheet.
	We have estimated the fair value of our contingent consideration as the present value of the expected payments over the term of the arrangements. The fair value measurement of our contingent consideration as of January 31, 2014 encompasses the following significant unobservable inputs:
	Unobservable Inputs		Range
	Total estimated contingent consideration		$0	-	$5,351
	Discount rate		9.50%	-	16.00%
	Timing of cash flows (in years)		0	-	4
	Changes in the fair value of our contingent consideration are primarily driven by changes in the estimated amount and timing of payments, resulting from changes in the forecasted revenues of the acquired businesses. Significant changes in any of the inputs in isolation could result in a fluctuation in the fair value measurement of contingent consideration. Changes in fair value are recognized in special charges in our consolidated statement of income in the period in which the change is identified.
	The following table summarizes contingent consideration activity:
	Balance as of January 31, 2012	$	6,120
	New contingent consideration	1,208
	Payments	(1,504		)
	Adjustments	(42		)
	Interest accretion	234
	Balance as of January 31, 2013	$	6,016
	New contingent consideration	540
	Payments	(1,266		)
	Adjustments	(898		)
	Interest accretion	179
	Balance as of January 31, 2014	$	4,571
	The following table summarizes the fair value and carrying value of notes payable:
	As of January 31,	2014				2013
	Fair value of notes payable	$	306,535			$	293,867
	Carrying value of notes payable	$	224,261			$	218,546
	We based the fair value of notes payable on the quoted market price at the balance sheet date. The quoted market price for our notes is derived from observable inputs including our stock price, stock volatility, and interest rate (Level 2). Of the total carrying value of notes payable, none was classified as current on our consolidated balance sheet as of January 31, 2014 and January 31, 2013.
	The carrying amounts of cash equivalents, trade accounts receivable, net, term receivables, short-term borrowings, accounts payable, and accrued liabilities approximate fair value because of the short-term nature of these instruments or because amounts have been appropriately discounted

Term_Receivable_and_Trade_Acco

Term Receivable and Trade Accounts Receivable Balances	12 Months Ended
	Jan. 31, 2014
Term Receivables and Trade Accounts Receivable [Abstract]	'
Term Receivables and Trade Accounts Receivable	'
	Term Receivables and Trade Accounts Receivable
	We have long-term installment receivables that are attributable to multi-year, multi-element term license sales agreements. We include balances under term agreements that are due within one year in trade accounts receivable, net and balances that are due more than one year from the balance sheet date in term receivables, long-term. We discount the total product portion of the agreements to reflect the interest component of the transaction. We amortize the interest component of the transaction, using the effective interest method, to system and software revenues over the period in which payments are made and balances are outstanding. We determine the discount rate at the outset of the arrangement based upon the current credit rating of the customer. We reset the discount rate periodically considering changes in prevailing interest rates but do not adjust previously discounted balances.
	Term receivable and trade accounts receivable balances were as follows:
	As of January 31,	2014		2013
	Trade accounts receivable	$	179,830	$	178,351
	Term receivables, short-term	$	274,653	$	233,894
	Term receivables, long-term	$	270,365	$	250,497
	Trade accounts receivable include billed amounts whereas term receivables, short-term is comprised of unbilled amounts. Term receivables, short term represent the portion of long-term installment agreements that are due within one year. Billings for term agreements typically occur thirty days prior to the contractual due date, in accordance with individual contract installment terms. Term receivables, long-term represent unbilled amounts which are scheduled to be collected beyond one year.
	We perform a credit risk assessment of all customers using the Standard & Poor’s (S&P) credit rating as our primary credit-quality indicator. The S&P credit ratings are based on the most recent S&P score available. For customers that do not have an S&P credit rating, we base our credit risk assessment on an internal credit assessment which is based on selected short-term financial ratios. Our internal credit assessment is based upon results provided in the customer's most recent financial statements.
	The credit risk assessment for our long-term receivables was as follows:
	As of January 31,	2014		2013
	S&P credit rating:
	AAA+ through BBB-	$	180,113	$	133,773
	BB+ and lower	29,654		45,298
		209,767		179,071
	Internal credit assessment	60,598		71,426
	Total long-term term receivables	$	270,365	$	250,497
	We maintain allowances for doubtful accounts on trade accounts receivable and term receivables, long-term for estimated losses resulting from the inability of our customers to make required payments. We regularly evaluate the collectibility of our trade accounts receivable based on a combination of factors. When we become aware of a specific customer’s inability to meet its financial obligations, such as in the case of bankruptcy or deterioration in the customer’s operating results, financial position, or credit rating, we record a specific reserve for bad debt to reduce the related receivable to the amount believed to be collectible. We also record unspecified reserves for bad debt for all other customers based on a variety of factors including length of time the receivables are past due, the financial health of the customers, the current business environment, and historical experience. Current economic conditions we have considered include forecasted spending in the semiconductor industry, consumer spending for electronics, integrated circuit research and development spending, and volatility in gross domestic product. If these factors change or circumstances related to specific customers change, we adjust the estimates of the recoverability of receivables resulting in either additional selling expense or a reduction in selling expense in the period the determination is made.
	The following shows the change in allowance for doubtful accounts for the years ended January 31, 2014, 2013, and 2012:
	Allowance for doubtful accounts	Beginning balance		Charged to		Other			Ending balance
				expense		changes(1)
	Year ended January 31, 2014	$	5,331	$	517	$	(379	)	$	5,469
	Year ended January 31, 2013	$	4,432	$	1,147	$	(248	)	$	5,331
	Year ended January 31, 2012	$	3,941	$	688	$	(197	)	$	4,432
	(1)	Specific account write-offs and foreign exchange.

ShortTerm_Borrowings

Short-Term Borrowings	12 Months Ended
	Jan. 31, 2014
Short-term Debt	'
Short-term Borrowings	'
	Short-Term Borrowings
	In May 2013, we amended our syndicated, senior, unsecured, revolving credit facility, extending the termination date to May 24, 2017.
	The revolving credit facility has a maximum borrowing capacity of $125,000. As stated in the revolving credit facility, we have the option to pay interest based on:
	(i)	London Interbank Offered Rate (LIBOR) with varying maturities commensurate with the borrowing period we select, plus a spread of between 2.00% and 2.50% based on a pricing grid tied to a financial covenant, or
	(ii)	A base rate plus a spread of between 1.00% and 1.50%, based on a pricing grid tied to a financial covenant.
	As a result of these interest rate options, our interest expense associated with borrowings under this revolving credit facility will vary with market interest rates.
	We had no borrowings against the revolving credit facility during fiscal 2014 or fiscal 2013. Commitment fees are payable on the unused portion of the revolving credit facility at rates between 0.30% and 0.40% based on a pricing grid tied to a financial covenant.
	The revolving credit facility contains certain financial and other covenants, including the following:
	•	Our adjusted quick ratio (ratio of the sum of cash and cash equivalents, short-term investments, and net current receivables to total current liabilities) shall not be less than 1.00;
	•	Our tangible net worth (stockholders' equity less goodwill and other intangible assets) must exceed the calculated required tangible net worth as defined in the credit agreement;
	•	Our leverage ratio (ratio of total liabilities less subordinated debt to the sum of subordinated debt and tangible net worth) shall be less than 2.00;
	•	Our senior leverage ratio (ratio of total debt less subordinated debt to the sum of subordinated debt and tangible net worth) shall not be greater than 0.90; and
	•	Our minimum cash and accounts receivable ratio (ratio of the sum of cash and cash equivalents, short-term investments, and 42.0% of net current accounts receivable, to outstanding credit agreement borrowings) shall not be less than 1.25.
	The revolving credit facility limits the aggregate amount we can pay for dividends and repurchases of our stock over the term of the facility of $50,000 plus 70% of our cumulative net income for periods after January 31, 2011.
	We were in compliance with all financial covenants as of January 31, 2014. If we fail to comply with the financial covenants and do not obtain a waiver from our lenders, we would be in default under the revolving credit facility and our lenders could terminate the facility and demand immediate repayment of all outstanding loans under the revolving credit facility.

Notes_Payable

Notes Payable	12 Months Ended
	Jan. 31, 2014
Notes Payable	'
	Notes Payable
	We have no long-term obligations maturing within the next five years. Our 4.00% Convertible Subordinated Debentures (4.00% Debentures) are due in 2031, but we may be required to repay them earlier under the conversion and redemption provisions described below.
	4.00% Debentures due 2031: In April 2011, we issued $253,000 of 4.00% Debentures in a private placement pursuant to the Securities and Exchange Commission Rule 144A under the Securities Act of 1933. Interest on the 4.00% Debentures is payable semi-annually in April and October.
	The 4.00% Debentures are convertible, under certain circumstances, into our common stock at a conversion rate, as of January 31, 2014, of 49.133 shares of our common stock for each one thousand dollars in principal amount of the 4.00% Debentures (equivalent to a conversion price of $20.35 per share) for a total of 12,431 shares. These circumstances include:
	•	The market price of our common stock exceeding 120% of the conversion price, or $24.42 per share as of January 31, 2014, for at least 20 of the last 30 trading days in the previous fiscal quarter;
	•	A call for redemption of the 4.00% Debentures;
	•	Specified distributions to holders of our common stock;
	•	If a fundamental change, such as a change of control, occurs;
	•	During the two months prior to, but not on, the maturity date; or
	•	The market price of the 4.00% Debentures declining to less than 98% of the value of the common stock into which the 4.00% Debentures are convertible.
	Upon conversion of any 4.00% Debentures, a holder will receive:
	(i)	Cash for the lesser of the principal amount of the 4.00% Debentures that are converted or the value of the converted shares; and
	(ii)	Cash or shares of common stock, at our election, for the excess, if any, of the value of the converted shares over the principal amount.
	As of January 31, 2014, the if-converted value of the 4.00% Debentures to the note holders exceeded the principal amount by $5,565.
	If a holder elects to convert their 4.00% Debentures in connection with a fundamental change in the company that occurs prior to April 5, 2016, the holder will also be entitled to receive a make whole premium upon conversion in some circumstances.
	As a result of declaring cash dividends during the year ended January 31, 2014, the initial conversion rate for the 4.00% Debentures of 48.6902 shares of our common stock for each one thousand dollars in principal amount of the 4.00% Debentures (equivalent to a conversion price of $20.54 per share of our common stock) has been adjusted to 49.133 shares of our common stock for each one thousand dollars in principal amount of the 4.00% Debentures (equivalent to a conversion price of $20.35 per share of our common stock).
	We may redeem some or all of the 4.00% Debentures for cash on or after April 5, 2016 at the following redemption prices expressed as a percentage of principal, plus any accrued and unpaid interest:
	Period	Redemption Price
	Beginning on April 5, 2016 and ending on March 31, 2017	101.143	%
	Beginning on April 1, 2017 and ending on March 31, 2018	100.571	%
	On April 1, 2018 and thereafter	100	%
	The holders, at their option, may redeem the 4.00% Debentures in whole or in part for cash on April 1, 2018, April 1, 2021, and April 1, 2026, and in the event of a fundamental change in the company. In each case, our repurchase price will be 100% of the principal amount of the 4.00% Debentures plus any accrued and unpaid interest.
	The 4.00% Debentures contain a conversion feature allowing for settlement of the debt in cash upon conversion, therefore we separately account for the implied liability and equity components of the 4.00% Debentures. The principal amount, unamortized debt discount, net carrying amount of the liability component, and carrying amount of the equity component of the 4.00% Debentures are as follows:
	As of	31-Jan-14			31-Jan-13
	Principal amount	$	253,000		$	253,000
	Unamortized debt discount	(28,739		)	(34,454		)
	Net carrying amount of the liability component	$	224,261		$	218,546
	Equity component	$	43,930		$	43,930
	The unamortized debt discount amortizes to interest expense using the effective interest method through March 2018.
	We recognized the following amounts in interest expense in the consolidated statement of operations related to the 4.00% Debentures:
	Year ended January 31,	2014			2013			2012
	Interest expense at the contractual interest rate	$	10,120		$	10,120		$	8,349
	Amortization of debt discount	$	5,715		$	5,322		$	4,154
	The effective interest rate on the 4.00% Debentures was 7.25% for fiscal 2014, fiscal 2013, and fiscal 2012.
	6.25% Debentures due 2026: During fiscal 2012, we redeemed the remaining $196,509 principal amount of the 6.25% Convertible Subordinated Debentures (6.25% Debentures) due 2026 utilizing proceeds received from the issuance of the 4.00% Debentures and cash on hand. In connection with this redemption, we incurred a before tax net loss on the early extinguishment of debt of $11,192, which included a $6,190 write-off of net unamortized debt discount, a $3,518 premium on redemption of the 6.25% Debentures, and a write-off of $1,484 for the unamortized debt issuance costs. This loss is included in interest expense in the consolidated statement of income. No balance remained outstanding following this redemption.
	We recognized the following amounts in interest expense in the consolidated statements of operations related to the 6.25% Debentures, issued 2006:
	Year ended January 31,	2014			2013			2012
	Interest expense at the contractual interest rate	$	—		$	—		$	2,900
	Amortization of debt discount	$	—		$	—		$	793
	Term Loan due 2013: In April 2010, we entered into a three-year term loan (Term Loan) for $20,000 to repay borrowings on our revolving credit facility used to purchase office buildings in Fremont, California. During fiscal 2012, we repaid the remaining obligation of $18,500 under the Term Loan utilizing proceeds received from the issuance of the 4.00% Debentures. In connection with this repayment, we incurred a before tax net loss on early retirement of debt of $312, representing the write-off of the unamortized debt issuance costs. This loss is included in interest expense on the consolidated statement of operations. No balance remained outstanding following this repayment.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Jan. 31, 2014
Commitments and Contingencies	'
	Commitments and Contingencies
	Leases
	We lease a majority of our field sales offices and research and development facilities under non-cancelable operating leases. In addition, we lease certain equipment used in our research and development and marketing and selling activities.
	Rent expense under operating leases was as follows:
	Year ended January 31,	2014		2013		2012
	Rent expense	$	27,240	$	26,597	$	27,535
	Future minimum lease payments under all non-cancelable operating leases are approximately as follows:
	Fiscal years ending January 31,	Lease
		Payments
	2015	$	23,117
	2016	18,372
	2017	11,927
	2018	6,601
	2019	3,343
	Thereafter	6,907
	Total	$	70,267
	Indemnifications
	Our license and services agreements generally include a limited indemnification provision for claims from third parties relating to our intellectual property. The indemnification is generally limited to the amount paid by the customer, a multiple of the amount paid by the customer, or a set cap. As of January 31, 2014, we were not aware of any material liabilities arising from these indemnifications.
	Legal Proceedings
	From time to time we are involved in various disputes and litigation matters that arise in the ordinary course of business. These include disputes and lawsuits relating to intellectual property rights, contracts, distributorships, and employee relations matters. Periodically, we review the status of various disputes and litigation matters and assess our potential exposure. When we consider the potential loss from any dispute or legal matter probable and the amount or the range of loss can be estimated, we will accrue a liability for the estimated loss. Legal proceedings are subject to uncertainties, and the outcomes are difficult to predict. Because of such uncertainties, we base accruals on the best information available at the time. As additional information becomes available, we reassess the potential liability related to pending claims and litigation matters and may revise estimates. We believe that the outcome of current litigation, individually and in the aggregate, will not have a material effect on our results of operations.
	In some instances, we are unable to reasonably estimate any potential loss or range of loss. The nature and progression of litigation can make it difficult to predict the impact a particular lawsuit will have. There are many reasons why we cannot make these assessments, including, among others, one or more of the following: the early stages of a proceeding; damages sought that are unspecific, unsupportable, unexplained or uncertain; discovery not having been started or incomplete; the complexity of the facts that are in dispute; the difficulty of assessing novel claims; the parties not having engaged in any meaningful settlement discussions; the possibility that other parties may share in any ultimate liability; and/or the often slow pace of litigation.
	In December 2012, Synopsys filed a lawsuit claiming patent infringement against us in federal district court in the Northern District of California, alleging that our Veloce family of products infringes on four Synopsys United States Patents. On May 2, 2013, Synopsys also filed a claim against us in federal district court in Oregon, similarly alleging that our Veloce family of products infringes on two additional Synopsys United States Patents. These cases seek compensatory damages and a permanent injunction against the licensing of several of our software and hardware products relating to our emulation and field programmable gate arrays synthesis products. We believe these actions were filed in response to patent lawsuits we filed in 2010 and 2012 against EVE, which Synopsys acquired in October 2012. Our lawsuits, which allege that EVE's Zebu emulation products infringe several of our patents, were filed against EVE in federal district court of Oregon. We also filed a patent lawsuit against EVE in Tokyo district court. Our litigation in Oregon and Japan seeks compensatory damages and an injunction against the sale of EVE emulation products. We do not have sufficient information upon which to determine that a loss in connection with this matter is probable, reasonably possible or estimable, and thus no liability has been established nor has a range of loss been disclosed.

Income_Taxes

Income Taxes	12 Months Ended
	Jan. 31, 2014
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	Income Taxes
	Domestic and foreign pre-tax income (loss) was as follows:
	Year ended January 31,	2014			2013			2012
	Domestic	$	(754	)	$	9,670		$	(62,943	)
	Foreign	163,822			131,665			145,267
	Total pre-tax income	$	163,068		$	141,335		$	82,324
	The provision (benefit) for income taxes was as follows:
	Year ended January 31,	2014			2013			2012
	Current:
	Federal	$	(366	)	$	(210	)	$	475
	State	355			(65		)	137
	Foreign	6,585			4,964			(2,731		)
	Total current	6,574			4,689			(2,119		)
	Deferred:
	Federal and state	1,333			350			695
	Foreign	1,603			(2,338		)	361
	Total deferred	2,936			(1,988		)	1,056
	Total provision (benefit) for income taxes	$	9,510		$	2,701		$	(1,063	)
	The actual income tax expense (benefit) is different from that which would have been computed by applying the statutory federal income tax rate to our income before income tax. A reconciliation of income tax expense (benefit) as computed at the U.S. federal statutory income tax rate to the provision (benefit) for income taxes is as follows:
	Year ended January 31,	2014			2013			2012
	Federal tax, at statutory rate	$	57,074		$	49,467		$	28,813
	State tax, net of federal benefit	355			(65		)	137
	Impact of international operations including withholding taxes and other reserves	(46,632		)	(50,275		)	(53,499		)
	Repatriation of foreign subsidiary earnings	20,367			12,661			1,364
	Foreign tax credits	(5,489		)	(8,203		)	(411		)
	Costs incurred for stock of acquired business	—			67			98
	Tax credits (excluding foreign tax credits)	(12,571		)	(11,782		)	(9,677		)
	Amortization of deferred charge	(2,311		)	—			323
	Change in valuation allowance	(5,929		)	5,978			28,275
	Stock-based compensation expense	2,593			1,895			2,947
	Non-deductible meals and entertainment	1,087			1,021			1,096
	Other, net	966			1,937			(529		)
	Provision (benefit) for income taxes	$	9,510		$	2,701		$	(1,063	)
	The tax effects of temporary differences and carryforwards, which gave rise to significant portions of deferred tax assets and liabilities, were as follows:
	As of January 31,	2014			2013
	Deferred tax assets:
	Depreciation of property, plant, and equipment	$	(8	)	$	274
	Reserves and allowances	10,733			10,398
	Accrued expenses not currently deductible	20,118			20,463
	Stock-based compensation expense	7,839			12,394
	Net operating loss carryforwards	40,245			55,612
	Tax credit carryforwards	90,852			75,639
	Purchased technology and other intangible assets	3,267			6,456
	Deferred revenue	3,680			3,097
	Other, net	4,844			7,853
	Total gross deferred tax assets	181,570			192,186
	Less valuation allowance	(126,989		)	(154,695		)
	Deferred tax assets	54,581			37,491
	Deferred tax liabilities:
	Intangible assets	(5,699		)	(8,286		)
	Undistributed foreign earnings	(32,132		)	(1,662		)
	Convertible debt	(11,276		)	(13,519		)
	Deferred tax liabilities	(49,107		)	(23,467		)
	Net deferred tax assets	$	5,474		$	14,024
	The above schedule includes short-term and long-term deferred tax assets and liabilities. Net long-term deferred tax liabilities are presented in our balance sheet in other long-term liabilities.
	As of January 31, 2014, we had the following foreign and U.S. Federal and state carryforwards for income tax purposes:
	Credit or carryforward	As of January 31,			Expiration
		2014
	Federal credits and carryforwards:
	Research and experimentation credit carryforward	$	70,201		Fiscal 2019 - 2034
	Net operating loss carryforward	$	179,123		Fiscal 2019 - 2032
	Foreign tax credits	$	14,335		Fiscal 2015 - 2024
	Alternative minimum tax credits	$	2,683		No expiration
Childcare credits	$	1,649		Fiscal 2023 - 2034
State income tax credits and carryforwards:
Net operating loss carryforward	$	213,490		Fiscal 2015 - 2033
Research and experimentation	$	18,026		Fiscal 2015 - 2029
Miscellaneous	$	1,199		Various
Foreign net operating loss carryforwards	$	34,122		Generally indefinite
Net operating loss carryforwards created by excess tax benefits from the exercise of stock options are not recorded as deferred tax assets. To the extent such net operating loss carryforwards are utilized, we will increase stockholders’ equity. For presentation purposes, we have elected to exclude the historic deferred tax assets related to excess tax benefits from stock option exercises. Our deferred tax assets related to net operating losses and tax credit carryforwards created by excess tax benefits from stock options have been reduced by $38,893 as of January 31, 2014 and $32,794 as of January 31, 2013.
The decrease in the valuation allowance largely resulted from the utilization of U.S. net operating losses and the expected use of additional U.S. net operating losses to offset actual tax impacts of accrued foreign subsidiary repatriations.
We have determined the amounts of our valuation allowances based on our estimates of taxable income by jurisdiction in which we operate over the periods in which the related deferred tax assets will be recoverable. We determined it is not more-likely-than-not that our U.S. entities will generate sufficient taxable income and foreign source income to fully utilize foreign tax credit carryforwards, research and experimentation credit carryforwards, and net operating loss carryforwards before expiration. Accordingly, we recorded a valuation allowance against those deferred tax assets for which realization does not meet the more-likely-than-not standard. Similarly, there is a valuation allowance on our state deferred tax assets due to the same uncertainties regarding future taxable U.S. income. We determine valuation allowances related to certain foreign deferred tax assets based on historical losses as well as future expectations in certain jurisdictions.
We have not provided for income taxes on the undistributed earnings of our foreign subsidiaries to the extent they are considered permanently re-invested outside the U.S. As of January 31, 2014, the cumulative amount of earnings upon which U.S. income taxes have not been provided is approximately $432,481. Upon repatriation, some of these earnings may be sheltered by U.S. loss carryforwards or foreign tax credits, which may reduce the federal tax liability associated with any future foreign dividend. Determination of the amount of unrecognized deferred U.S. income tax liability on permanently re-invested earnings is not practicable. Where the earnings of our foreign subsidiaries are not treated as permanently re-invested, we have considered the impact in our tax provision.
We are subject to income taxes in the U.S. and in numerous foreign jurisdictions. In the ordinary course of business, there are many transactions and calculations where the ultimate tax determination is uncertain. The statute of limitations for adjustments to our historic tax obligations will vary from jurisdiction to jurisdiction. In some cases it may be extended or be unlimited. Furthermore, net operating loss and tax credit carryforwards may be subject to adjustment after the expiration of the statute of limitations of the year such net operating losses and tax credits originated. Our larger jurisdictions generally provide for a statute of limitation from three to five years. For U.S. federal income tax purposes, the tax years which remain open for examination are fiscal years 2011 and forward, although net operating loss and credit carryforwards from all years are subject to examination and adjustment for three years following the year in which utilized. We are currently under examination in various jurisdictions. The examinations are in different stages and timing of their resolution is difficult to predict. The statute of limitations remains open for years on or after fiscal 2010 in Ireland.
We have reserves for taxes to address potential exposures involving tax positions that are being challenged or that could be challenged by the tax authorities even though we believe the positions we have taken are appropriate. We believe our tax reserves are adequate to cover potential liabilities. We review the tax reserves as circumstances warrant and adjust the reserves as events occur that affect our potential liability for additional taxes. It is often difficult to predict the final outcome or timing of resolution of any particular tax matter. Various events, some of which cannot be predicted, such as clarification of tax law by administrative or judicial means, may occur and would require us to increase or decrease our reserves and effective tax rate. It is reasonably possible that existing unrecognized tax benefits may decrease from $0 to $4,000 due to settlements or expiration of the statute of limitations within the next twelve months. To the extent that uncertain tax positions resolve in our favor, it could have a positive impact on our effective tax rate. A portion of our reserves, which could settle or expire within the next twelve months, may result in deferred tax assets subject to a valuation allowance for which no benefit would be recognized. Income tax-related interest and penalties were a benefit of $1,710 for the year ended January 31, 2014, a benefit of $297 for the year ended January 31, 2013 and an expense of $677 for the year ended January 31, 2012.
The below schedule shows the gross changes in unrecognized tax benefits associated with uncertain tax positions for the years ending January 31, 2014 and 2013:
Unrecognized tax benefits as of January 31, 2012	$	41,905
Gross increases—tax positions in prior period	457
Gross decreases—tax positions in prior period	(7		)
Gross increases—tax positions in current period	4,316
Lapse of statute of limitations	(7,553		)
Cumulative translation adjustment	(336		)
Unrecognized tax benefits as of January 31, 2013	$	38,782
Gross increases—tax positions in prior period	3,863
Gross decreases—tax positions in prior period	(10,313		)
Gross increases—tax positions in current period	3,900
Gross decreases-tax positions current	—
Settlements	(1,581		)
Lapse of statute of limitations	(2,982		)
Cumulative translation adjustment	(348		)
Unrecognized tax benefits as of January 31, 2014	$	31,321
The ending balances of unrecognized tax benefits represent the gross amount of exposure in individual jurisdictions and do not reflect any additional benefits expected to be realized if such positions were not sustained, such as the federal deduction that could be realized if an unrecognized state deduction was not sustained. The ending gross balances exclude accrued interest and penalties related to such positions of $7,687 as of January 31, 2014 and $9,538 as of January 31, 2013. We expect that $18,674 of our unrecognized tax benefits, if recognized, would favorably affect our effective tax rate.

Employee_Stock_and_Savings_Pla

Employee Stock and Savings Plans	12 Months Ended
	Jan. 31, 2014
Share-based Compensation [Abstract]	'
Employee Stock and Savings Plans	'
	Employee Stock and Savings Plans and Stockholders' Equity
	Stock Options Plans and Stock Plans
	Our 2010 Omnibus Incentive Plan (Incentive Plan) is administered by the Compensation Committee of our Board of Directors and permits accelerated vesting of outstanding options, restricted stock units, restricted stock awards, and other equity incentives upon the occurrence of certain changes in control of our company.
	Stock options and restricted stock units under the Incentive Plan are generally expected to vest over four years. Stock options have an expiration date of ten years from the date of grant and an exercise price no less than the fair market value of the shares on the date of grant. The source of shares issued under the Incentive Plan is new shares.
	During fiscal 2014, restricted stock units with a performance condition were granted to certain officers. Vesting of these restricted stock units occurs after three years and is dependent upon attainment of goals for operating income margin.
	As of January 31, 2014, a total of 3,993 shares of common stock were available for future grant under the Incentive Plan.
	Stock options outstanding, the weighted average exercise price, and transactions involving stock options are summarized as follows:
		Options		Weighted				Weighted		Aggregate
		Outstanding		Average				Average		Intrinsic
				Exercise				Remaining		Value
				Price				Contractual
								Terms
								(Years)
	Balance as of January 31, 2013	6,717		$	11.08
	Granted	—		—
	Exercised	(3,124	)	12.43
	Forfeited	3		4.2
	Expired	(9	)	12.37
	Balance as of January 31, 2014	3,587		9.87				5.38		$	39,195
	Options exercisable as of January 31, 2014	2,933		8.94				4.79		34,784
	Options vested as of January 31, 2014 and options expected to vest after January 31, 2014	3,587		$	9.87			5.38		$	39,195
	The total intrinsic value of options exercised and cash received from options exercised was as follows:
	Year ended January 31,	2014			2013				2012
	Intrinsic value	$	26,769		$	21,647			$	15,802
	Cash received	$	38,830		$	24,262			$	15,194
	The following table summarizes restricted stock activity (including the target number of shares awarded under performance-based restricted stock units):
		Restricted		Weighted				Weighted		Aggregate
		Stock Units		Average Grant				Average		Intrinsic
				Date Fair Value				Remaining		Value
								Contractual Term
								(Years)
	Nonvested as of January 31, 2013	3,996		$	13.39
	Granted	1,616		22.42
	Vested	(1,374	)	12.93
	Forfeited	(155	)	14.83
	Nonvested as of January 31, 2014	4,083		$	17.07			1.6		$	84,925
	The following table summarizes the fair value of restricted stock units vested:
	Year ended January 31,	2014			2013				2012
	Total fair value of restricted stock units vested	$	17,736		$	11,698			$	5,446
	Employee Stock Purchase Plans
	We have an ESPP for U.S. employees and an ESPP for certain foreign subsidiary employees. The ESPPs provide for six month offerings commencing on January 1 and July 1 of each year with purchases on June 30 and December 31 of each year. Each eligible employee may purchase up to six thousand shares of stock on each purchase date at prices no less than 85% of the lesser of the fair market value of the shares on the offering date or on the purchase date. As of January 31, 2014, 2,547 shares remain available for future purchase under the ESPPs.
	The following table summarizes shares issued under the ESPPs:
	Year ended January 31,	2014			2013				2012
	Shares issued under the ESPPs	1,554			1,884				2,099
	Cash received for the purchase of shares under the ESPPs	$	23,895		$	22,645			$	22,155
	Weighted average purchase price per share	$	15.38		$	12.02			$	10.55
	Stock-Based Compensation Expense
	We estimate the fair value of the purchase rights under our ESPPs and stock options using a Black-Scholes option-pricing model. The Black-Scholes option-pricing model incorporates several highly subjective assumptions including expected volatility, expected term, and interest rates.
	In determining expected volatility for options, we include the elements listed below at the weighted percentages presented:
	•	Historical volatility of our shares of common stock at 35%;
	•	Historical volatility of shares of comparable companies at 20%;
	•	Implied volatility of our traded options at 30%; and
	•	Implied volatility of traded options of comparable companies at 15%.
	The greatest weighting is provided to our historic volatility based on the amount of consistent historic information available. A lesser weighting is applied to the implied volatility of our traded options due to a low volume of trades and shorter terms. We also include the historic and implied volatility of comparable companies in our industry in an effort to capture a broader view of the marketplace.
	The relative weighting percentages are periodically reviewed for reasonableness and are subject to change depending on market conditions and our particular facts and circumstances.
	The expected volatility for the purchase rights for our ESPPs is based on the historical volatility of our shares of common stock. The expected term for the purchase rights for our ESPPs is the 6 month offering period.
	We base the expected term of our stock options on historical experience.
	The risk-free interest rate for periods within the contractual life of the purchase rights under our ESPPs and stock options is based on the U.S. Treasury yield curve in effect at the time of the grant.
	The fair value of restricted stock units is the market value as of the grant date.
	The weighted average grant date fair values are summarized as follows:
	Year ended January 31,	2014			2013				2012
	Options granted	$	—		$	7.18			$	5.43
	Restricted stock units granted	$	22.42		$	16.74			$	10.91
ESPP purchase rights	$	4.3		$	3.82			$	3.19
The fair value calculations used the following assumptions:
Year ended January 31,	2014		2013			2012
Stock Option Plans
Risk-free interest rate	—		0.9% - 1.3%			1.2	%
Dividend yield	—		0	%		0	%
Expected life (in years)	—		5.8 - 6.3			6.3
Volatility (range)	—		43% - 53%			53	%
Volatility (weighted average)	—		43	%		53	%
Year ended January 31,	2014		2013			2012
Employee Stock Purchase Plans
Risk-free interest rate	0.09% - 0.14%		0.05% - 0.15%			0.05% - 0.18%
Dividend yield (range)	0% - 1%		0	%		0	%
Dividend yield (weighted average)	0.5	%	0	%		0	%
Expected life (in years)	0.5		0.5			0.5
Volatility (range)	22% - 33%		33% - 43%			32% - 38%
Volatility (weighted average)	29	%	39	%		35	%
The following table summarizes stock-based compensation expense included in the results of operations and the tax benefit associated with the exercise of stock options:
Year ended January 31,	2014			2013				2012
Cost of revenues:
Service and support	$	1,992		$	1,529			$	1,065
Operating expense:
Research and development	11,182			9,206				8,203
Marketing and selling	7,777			6,654				5,874
General and administration	8,399			6,308				6,516
Equity plan-related compensation expense	$	29,350		$	23,697			$	21,658
Tax effect of the exercise of stock options	$	386		$	266			$	—
As of January 31, 2014, we had $3,580 in unrecognized compensation cost related to nonvested options which is expected to be recognized over a weighted average period of 1.1 years and $58,964 in unrecognized compensation cost related to nonvested restricted stock units which is expected to be recognized over a weighted average period of 1.5 years.
Employee Savings Plan
We have an employee savings plan (the Savings Plan) that qualifies as a deferred salary arrangement under Section 401(k) of the Internal Revenue Code. Under the Savings Plan, participating U.S. employees may defer a portion of their pretax earnings, up to the Internal Revenue Service annual contribution limit. We currently match 50% of eligible employee’s contributions, up to a maximum of 6% of the employee’s earnings. Employer matching contributions vest over five years, 20% for each year of service completed. Our matching contributions to the Savings Plan were as follows:
Year ended January 31,	2014			2013				2012
Employer matching contribution	$	7,708		$	7,181			$	7,141
Dividends
On March 7, 2013, our Board of Directors announced the adoption of a dividend policy under which we commenced payment of cash dividends at an annual rate of $0.18 per share of common stock. On February 27, 2014, we announced an increase to the quarterly dividend to $0.05 per share. The following table summarizes the dividends declared:
Declaration Date		Record Date	Payment Date		Per Share Amount				Total Amount
3/7/13		3/22/13	4/10/13		$	0.045			$	5,064
5/23/13		6/10/13	7/1/13		$	0.045			$	5,079
8/22/13		9/10/13	9/30/13		$	0.045			$	5,096
11/21/13		12/10/13	1/2/14		$	0.045			$	5,159
2/27/14		3/10/14	3/31/14		$	0.05
Future declarations of quarterly dividends and the establishment of future record and payment dates are subject to the quarterly determination of our Board of Directors.

Incentive_Stock_Rights

Incentive Stock Rights	12 Months Ended
	Jan. 31, 2014
Notes To Financial Statements [Abstract]	'
Incentive Stock Rights	'
	Incentive Stock Rights
	Our Board of Directors has the authority to issue incentive stock in one or more series and to determine the relative rights and preferences of the incentive stock. On June 24, 2010, we adopted an Incentive Stock Purchase Rights Plan and declared a dividend distribution of one right for each outstanding share of common stock, payable to holders of record on July 6, 2010. On December 23, 2011 our Board of Directors amended the Stock Purchase Rights Plan to, among other things, extend the expiration date of the rights and increase the exercise price of each right. On June 28, 2013, our Board of Directors amended the Stock Purchase Rights Plan to extend the expiration date of the rights, change the ownership threshold for certain types of investors, increase the exercise price of each right, and add a qualifying offer provision. As long as the rights are attached to our common stock, we will issue one right with each new share of common stock so that all such shares will have attached rights. Under certain conditions, each right may be exercised to purchase 1/10,000 of a share of Series B Junior Participating Incentive Stock at a purchase price of ninety dollars, subject to adjustment. The rights are not presently exercisable and will only become exercisable if a person or group acquires or commences a tender offer to acquire 15% (20% for certain types of "passive institutional investors") or more of our common stock.
	If a person or group acquires 15% (20% for certain types of "passive institutional investors") or more of our common stock, each right will be adjusted to entitle its holder to receive, upon exercise, common stock (or, in certain circumstances, other assets of ours) having a value equal to two times the exercise price of the right, or each right will be adjusted to entitle its holder to receive, upon exercise, common stock of the acquiring company having a value equal to two times the exercise price of the right, depending on the circumstances. The rights expire on June 30, 2015 and may be redeemed by us for $0.001 per right. The rights do not have voting or dividend rights and have no dilutive effect on our earnings.

Net_Income_Per_Share

Net Income Per Share	12 Months Ended
	Jan. 31, 2014
Earnings Per Share [Abstract]	'
Earnings Per Share	'
	Net Income Per Share
	The following provides the computation of basic and diluted net income per share:
	Year ended January 31,	2014			2013			2012
	Net income attributable to Mentor Graphics shareholders	$	155,258		$	138,736		$	83,872
	Noncontrolling interest adjustment to redemption value	(4,486		)	(5,272		)	—
	Adjusted net income attributable to Mentor Graphics shareholders	$	150,772		$	133,464		$	83,872
	Weighted average common shares used to calculate basic net income per share	113,671			110,998			110,138
	Employee stock options, restricted stock units and employee stock purchase plan	3,031			3,019			2,777
	Weighted average common and potential common shares used to calculate diluted net income per share	116,702			114,017			112,915
	Net income per share attributable to Mentor Graphics shareholders:
	Basic	$	1.33		$	1.2		$	0.76
	Diluted	$	1.29		$	1.17		$	0.74
	We excluded from the computation of diluted net income per share stock options, restricted stock units, and ESPP purchase rights to purchase 1,195 shares of common stock for the year ended January 31, 2014, 1,975 for fiscal 2013, and 4,056 for fiscal 2012. The stock options, restricted stock units, and ESPP purchase rights were determined to be anti-dilutive as a result of applying the treasury stock method.
	We have decreased the numerator of our basic and diluted earnings per share calculation for the adjustment of the noncontrolling interest with redemption feature to its calculated redemption value at January 31, 2014 and January 31, 2013, recorded directly to retained earnings. For the year ended January 31, 2012, we excluded a similar adjustment of $1,682 from the calculation of basic and diluted earnings per share, as the amount was not significant.
	The effect of the conversion of the 4.00% Debentures was anti-dilutive and therefore excluded from the computation of diluted net income per share. We assume that the 4.00% Debentures will be settled in common stock for purposes of calculating the dilutive effect on net income per share. If the 4.00% Debentures had been dilutive we would have included additional income of $2,075 for the years ended January 31, 2014, 2013 and 2012. Dilutive net income per share would have included no incremental shares for the years ended January 31, 2014, 2013, or 2012 as the average stock price for the period was below the conversion rate.
	The conversion features of the 4.00% Debentures, which allow for settlement in cash, common stock, or a combination of cash and common stock, are further described in Note 6. “Notes Payable.”

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income	12 Months Ended
	Jan. 31, 2014
Accumulated Other Comprehensive Income	'
	Accumulated Other Comprehensive Income
	The following table summarizes the components of accumulated other comprehensive income, net of tax:
	As of January 31,	2014		2013
	Foreign currency translation adjustment	$	18,361	$	25,146
	Unrealized gain (loss) on derivatives	42		(12		)
	Pension liability	400		265
	Total accumulated other comprehensive income	$	18,803	$	25,399

Special_Charges

Special Charges	12 Months Ended
	Jan. 31, 2014
Restructuring and Related Activities [Abstract]	'
Special Charges	'
	Special Charges
	The following is a summary of the components of the special charges:
	Year ended January 31,	2014		2013		2012
	Litigation costs	$	11,597	$	3,632	$	—
	Employee severance and related costs	4,392		4,016		8,437
	Other	940		2,298		4,737
	Total special charges	$	16,929	$	9,946	$	13,174
	Special charges may include expenses incurred related to certain litigation costs, employee severance, acquisitions, excess facility costs, and asset related charges.
	Litigation costs consist of professional service fees for services rendered, related to patent litigation involving us, EVE, and Synopsys regarding emulation technology. For the year ended January 31, 2013, these costs have been reclassified from general and administration to special charges as further described in Note 2. "Summary of Significant Accounting Policies."
	Employee severance and related costs include severance benefits, notice pay, and outplacement services. These rebalance charges generally represent the aggregate of numerous unrelated rebalance plans which impact several employee groups, none of which is individually material to our financial position or results of operations. We determine termination benefit amounts based on employee status, years of service, and local statutory requirements. We communicate termination benefits to the affected employees prior to the end of the quarter in which we record the charge.
	Approximately 80% of the employee severance and related costs for fiscal 2014 were paid during fiscal 2014. We expect to pay the remainder during fiscal 2015. Approximately 60% of the employee severance and related costs for fiscal 2013 were paid during fiscal 2013. Costs remaining as of January 31, 2013 were paid in fiscal 2014. Approximately 61% of the employee severance and related costs for fiscal 2012 were paid during fiscal 2012. Costs remaining as of January 31, 2012 were paid in fiscal 2013. There have been no significant modifications to the amount of these charges.
	Other special charges for fiscal 2012 primarily consisted of costs of $4,066 for advisory fees associated with our proxy contest.
	Accrued special charges are included in accrued and other liabilities and other long-term liabilities in the consolidated balance sheets. The following table shows changes in accrued special charges during the year ended January 31, 2014:
		Accrued special		Charges during		Payments during			Accrued special
		charges as of		the year ended		the year ended			charges as of
		31-Jan-13		31-Jan-14		31-Jan-14			31-Jan-14		(1)
	Litigation costs	$	624	$	11,597	$	(7,366	)	$	4,855
	Employee severance and related costs	2,028		4,392		(5,416		)	1,004
	Other costs	2,889		940		(1,842		)	1,987
	Accrued special charges	$	5,541	$	16,929	$	(14,624	)	$	7,846
	(1)	Of the $7,846 total accrued special charges as of January 31, 2014, $587 represented the long-term portion, which primarily included accrued lease termination fees and other facility costs, net of sublease income and other long-term costs. The remaining balance of $7,259 represented the short-term portion of accrued special charges.
	The following table shows changes in accrued special charges during the year ended January 31, 2013:
		Accrued special		Charges during		Payments during			Accrued special
		charges as of		the year ended		the year ended			charges as of
		31-Jan-12		31-Jan-13		31-Jan-13			31-Jan-13		(1)
	Litigation costs	$	—	$	3,632	$	(3,008	)	$	624
	Employee severance and related costs	3,668		4,016		(5,656		)	2,028
	Other costs	2,811		2,298		(2,220		)	2,889
	Accrued special charges	$	6,479	$	9,946	$	(10,884	)	$	5,541
	(1)	Of the $5,541 total accrued special charges as of January 31, 2013, $2,213 represented the long-term portion, which primarily included accrued lease termination fees and other facility costs, net of sublease income. The remaining balance of $3,328 represented the short-term portion of accrued special charges.
	The following table shows changes in accrued special charges during the year ended January 31, 2012:
		Accrued special		Charges during		Payments during			Accrued special
		charges as of		the year ended		the year ended			charges as of
		31-Jan-11		31-Jan-12		31-Jan-12			31-Jan-12		(1)
	Employee severance and related costs	$	2,664	$	8,437	$	(7,433	)	$	3,668
	Other costs	4,266		4,737		(6,192		)	2,811
	Accrued special charges	$	6,930	$	13,174	$	(13,625	)	$	6,479
	(1)	Of the $6,479 total accrued special charges as of January 31, 2012, $2,173 represented the long-term portion, which primarily included accrued lease termination fees and other facility costs, net of sublease income. The remaining balance of $4,306 represented the short-term portion of accrued special charges.

Other_Income_Expense_Net

Other Income (Expense), Net	12 Months Ended
	Jan. 31, 2014
Other Income (Expense), Net	'
	Other Income (Expense), Net
	Other income (expense), net was comprised of the following:
	Year ended January 31,	2014			2013			2012
	Interest income	$	2,360		$	1,944		$	2,195
	Foreign currency exchange loss	(1,872		)	(2,394		)	(718		)
	Gain on conversion of equity method investment to controlling interest	—			—			1,519
	Other, net	(1,008		)	(982		)	(1,420		)
	Other income (expense), net	$	(520	)	$	(1,432	)	$	1,576
	In fiscal 2012, we exchanged one of our product lines for a controlling interest in a privately-held company. Prior to acquiring this controlling interest, we had a noncontrolling interest, which was accounted for under the equity method of accounting. As a result of this transaction, we recognized a gain of $1,519 to adjust the carrying value of our equity method investment in the company to its fair value based on an income approach valuation method.

Related_Party_Transactions

Related Party Transactions	12 Months Ended
	Jan. 31, 2014
Related Party Transactions [Abstract]	'
Related Party Transactions	'
	Related Party Transactions
	Certain members of our Board of Directors also serve as officers or directors for some of our customers. Management believes the transactions between these customers and us were carried out on an arm’s-length basis. As of January 31, 2014, we had amounts receivable from these customers of $95,789. As of January 31, 2013, accounts receivable from these customers were not significant. The following table shows revenue recognized from these customers:
	Year ended January 31,	2014			2013			2012
	Revenue from customers	$	85,037		$	56,878		$	35,944
	Percentage of total revenues	7.4		%	5.2		%	3.5		%

Supplemental_Cash_Flow_Informa

Supplemental Cash Flow Information	12 Months Ended
	Jan. 31, 2014
Supplemental Cash Flow Information [Abstract]	'
Supplemental Cash Flow Information	'
	Supplemental Cash Flow Information
	The following provides information concerning supplemental disclosures of cash flow activities:
	Year ended January 31,	2014		2013		2012
	Cash paid for:
	Interest	$	12,225	$	11,981	$	14,686
	Income taxes	$	11,871	$	10,777	$	8,707
	We have an investment in Frontline. We received returns on investment of $5,500 during fiscal 2014, $6,250 during fiscal 2013 and $7,015 during fiscal 2012 which is included in net cash provided by operating activities in our consolidated statement of cash flows.

Segment_Reporting

Segment Reporting	12 Months Ended
	Jan. 31, 2014
Segment Reporting [Abstract]	'
Segment Reporting	'
	Segment Reporting
	Our Chief Operating Decision Makers (CODMs), which consist of the Chief Executive Officer and the President, review our consolidated results within one operating segment. In making operating decisions, our CODMs primarily consider consolidated financial information accompanied by disaggregated revenue information by geographic region.
	We eliminate all intercompany revenues in computing revenues by geographic regions. Revenues and property, plant and equipment, net, related to operations in the geographic areas were:
	Year ended January 31,	2014		2013		2012
	Revenues:
	United States	$	497,954	$	467,595	$	397,801
	Other North America	15,250		13,544		18,361
	Total North America	513,204		481,139		416,162
	Europe	241,417		261,371		247,079
	Japan	113,796		127,789		116,469
	Pacific Rim	287,956		218,428		234,928
	Total revenues	$	1,156,373	$	1,088,727	$	1,014,638
	For the years ended January 31, 2014, 2013 and 2012, no single customer accounted for 10% or more of our total revenues.
	As of January 31,	2014		2013
	Property, plant, and equipment, net:
	United States	$	116,954	$	121,179
	Other North America	141		269
	Total North America	117,095		121,448
	Europe	34,800		33,029
	Japan	637		979
	Pacific Rim	7,633		6,946
	Total property, plant and equipment, net	$	160,165	$	162,402

Quarterly_Financial_Informatio

Quarterly Financial Information - Unaudited	12 Months Ended
	Jan. 31, 2014
Quarterly Financial Information Disclosure [Abstract]	'
Quarterly Financial Information	'
	Quarterly Financial Information – Unaudited
	A summary of quarterly financial information follows:
	Quarter ended	April 30		July 31			October 31			January 31
	Fiscal 2014
	Total revenues	$	226,515	$	253,216		$	275,642		$	401,000
	Gross profit	$	186,334	$	208,359		$	229,570		$	345,003
	Operating income	$	5,893	$	26,578		$	33,372		$	117,197
	Net income attributable to Mentor Graphics shareholders	$	205	$	23,982		$	25,535		$	105,536
	Net income per share, basic (1)	$	0.01	$	0.19		$	0.21		$	0.91
	Net income per share, diluted (1)	$	0.01	$	0.19		$	0.2		$	0.89
	Fiscal 2013
	Total revenues	$	247,918	$	240,811		$	268,760		$	331,238
	Gross profit	$	202,535	$	194,235		$	218,497		$	283,770
	Operating income	$	32,822	$	19,907		$	37,809		$	71,095
	Net income attributable to Mentor Graphics shareholders	$	28,182	$	18,167		$	30,641		$	61,746
	Net income per share, basic (1)	$	0.26	$	0.17		$	0.27		$	0.5
	Net income per share, diluted (1)	$	0.25	$	0.16		$	0.27		$	0.49
	(1) We have adjusted the numerator of our earnings per share calculation by the following for the adjustment of our noncontrolling interest to the calculated redemption value, recorded directly to retained earnings:
	Quarter ended	30-Apr		31-Jul			31-Oct			31-Jan
	Fiscal 2014	$	468	$	(2,349	)	$	(2,032	)	$	(573	)
	Fiscal 2013	$	—	$	—		$	—		$	(5,272	)

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Jan. 31, 2014				Jan. 31, 2013
Accounting Policies [Abstract]	'				'
Principles of Consolidation	'				'
	Principles of Consolidation
	The consolidated financial statements include our financial statements and those of our wholly-owned and majority-owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation.
	We do not have off-balance sheet arrangements, financings, or other similar relationships with unconsolidated entities or other persons, also known as special purpose entities. In the ordinary course of business, we lease certain real properties, primarily field sales offices, research and development facilities, and equipment, as described in Note 8. “Commitments and Contingencies.”
Foreign Currency Translation	'				'
	Foreign Currency Translation
	Local currencies are the functional currencies for our foreign subsidiaries except for certain subsidiaries in Ireland, Singapore, Egypt, and the Netherlands Antilles where the United States (U.S.) dollar is used as the functional currency. We translate assets and liabilities of foreign operations, excluding certain subsidiaries in Ireland, Singapore, Egypt, and the Netherlands Antilles to U.S. dollars at current rates of exchange and revenues and expenses using weighted average rates. We include foreign currency translation adjustments in stockholders’ equity as a component of accumulated other comprehensive income. We maintain the accounting records for certain subsidiaries in Ireland, Singapore, Egypt, and the Netherlands Antilles in the U.S. dollar and accordingly no translation is necessary. We include foreign currency transaction gains and losses as a component of other income (expense), net.
Use of Estimates	'				'
	Use of Estimates
	U.S. generally accepted accounting principles require management to make estimates and assumptions that affect the reported amount of assets, liabilities, and contingencies at the date of the financial statements and the reported amounts of revenues and expenses during the reporting periods. Such estimates include valuation of accounts receivable, revenue recognition, business combinations, income taxes, goodwill, intangible assets, long-lived assets, special charges, and stock-based compensation. These estimates and assumptions are based on our best judgment. We evaluate our estimates and assumptions on an ongoing basis using historical experience and other factors, including the current economic environment, which we believe to be reasonable under the circumstances. We adjust estimates and assumptions as facts and circumstances dictate. Actual results could differ from these estimates. Any changes in estimates will be reflected in the financial statements in future periods.
Investments	'				'
	Investments
	We classify investments with original maturities of 90 days or less as cash equivalents. Short-term investments include certificates of deposit with original maturities in excess of 90 days and less than one year at the time of purchase.
	Long-term investments, included in other assets on the accompanying consolidated balance sheets, include investments with maturities in excess of one year from the balance sheet date and equity securities. We determine the appropriate classification of our investments at the time of purchase. For investments in equity securities, we use the equity method of accounting when our investment gives us the ability to exercise significant influence over the operating and financial policies of the investee. Under the equity method, we currently record our share of earnings or losses as a component of other income (expense), net, equal to our proportionate share of the earnings or losses of the investee. For investments in equity securities of private companies without a readily determinable fair value, and as to which we do not exercise significant influence over the investee, we record our investment under the cost method of accounting. Under the cost method of accounting, we carry the investment at historical cost. We periodically evaluate the fair value of all investments to determine if an other-than-temporary decline in value has occurred.
Investment in Frontline	'				'
	Investment in Frontline
	We have a 50% interest in a joint venture, Frontline P.C.B. Solutions Limited Partnership (Frontline), a provider of engineering software solutions for the printed circuit board industry. We use the equity method of accounting for Frontline, which results in reporting our investment as one line within other assets in the consolidated balance sheet and our share of earnings on one line in the consolidated statement of income. Frontline reports on a calendar year basis. As such, we record our interest in the earnings of Frontline on a one-month lag.
	Although we do not exert control, we actively participate in regular and periodic activities with respect to Frontline such as budgeting, business planning, marketing, and direction of research and development projects. Accordingly, we have included our interest in the earnings of Frontline as a component of operating income.
Property, Plant, and Equipment, Net	'				'
	Property, Plant, and Equipment, Net
	We state property, plant, and equipment at cost and capitalize expenditures for additions to property, plant, and equipment. We expense maintenance and repairs which do not improve or extend the life of the respective asset as incurred. We compute depreciation on a straight-line basis as follows:
		Estimated Useful Lives (in years)
	Buildings		40
	Land improvements		20
	Computer equipment and furniture	3	-	5
	Leasehold improvements(1)	3	-	10
Goodwill and Intangible Assets	'				'
	Goodwill and Intangible Assets
	Goodwill represents the excess of the aggregate purchase price over the fair value of the net tangible assets and other intangible assets acquired in our business combinations. Intangible assets, net primarily includes purchased technology, in-process research and development, backlog, tradename, and customer relationships acquired in our business combinations. We review long-lived assets, including intangible assets with definite lives, for impairment whenever events or changes in circumstances indicate the carrying amount of such assets may not be recoverable. We assess the recoverability of our long-lived assets by determining whether the carrying values of the asset groups are greater than the forecasted undiscounted net cash flows of the related asset group. If we determine the assets are impaired, we write down the assets to their estimated fair value. We determine fair value based on forecasted discounted net cash flows or appraised values, depending upon the nature of the assets. In the event we determine our long-lived assets have been impaired, we would make an adjustment that would result in a charge for the write-down in the period that the determination was made.
	Goodwill is not amortized, but is tested for impairment at least annually and as necessary if changes in facts and circumstances indicate that the fair value of our reporting unit may be less than the carrying amount. We operate as a single reporting unit for purposes of goodwill evaluation. We completed our annual goodwill impairment test as of January 31, 2014, 2013, and 2012. For purposes of assessing the impairment of goodwill, we estimated the fair value of our reporting unit using its market capitalization as the best evidence of fair value and then compared the fair value to the carrying value of our reporting unit. Our reporting unit passed this step of the goodwill analysis. There were no indicators of impairment to goodwill during fiscal 2014, 2013, and 2012 and accordingly, no impairment charges were recognized during these fiscal periods.
	We amortize purchased technology over three to five years to system and software cost of revenues and other intangible asset costs over one to five years to operating expenses. We amortize capitalized in-process research and development (resulting from acquisitions), upon completion of projects to cost of revenues over the estimated useful life of the technology. Alternatively, if we abandon a project, in-process research and development costs are expensed to operating expense when that determination is made.
Noncontrolling Interest with Redemption Feature	'				'
	Noncontrolling Interest with Redemption Feature
	As of January 31, 2014, our balance sheet includes a noncontrolling interest resulting from a business combination in which we acquired majority ownership in a privately-held company. In conjunction with this business combination, we also entered into an agreement which provides us a call option to acquire the noncontrolling interest and the noncontrolling interest holders a put option to sell their interests to us for prices based on formulas defined in the agreement. The noncontrolling interest adjusted for this redemption feature based on the put option price formula, is presented on the consolidated balance sheet under the caption “Noncontrolling interest with redemption feature.” Because the redemption of the noncontrolling interest is outside of our control, we have presented this interest outside of stockholders’ equity.
	The noncontrolling interest with redemption feature is recognized at the greater of:
	i. The calculated redemption put value as of the balance sheet date; or
	ii. The initial noncontrolling interest value adjusted for the noncontrolling interest holders' share of:
	a. cumulative impact of net income (loss); and
	b. other changes in accumulated other comprehensive income.
	Increases (or decreases to the extent they offset previous increases) in the calculated redemption feature put value are recorded directly to retained earnings as if the balance sheet date were also the redemption date. Changes in the redemption feature put value, to the extent they are significant, also result in an adjustment to net income attributable to shareholders in the calculation of basic and diluted net income per share.
	The results of the majority-owned subsidiary are presented in our consolidated results with an adjustment reflected on the face of our statement of income and the face of our statement of comprehensive income for the noncontrolling investors' interest in the results of the subsidiary.
Income Taxes	'				'
	Income Taxes
	We use the asset and liability method of accounting for income taxes. Under this method, we recognize deferred income taxes for the future tax consequences attributable to temporary differences between the financial statement carrying amounts and tax balances of existing assets and liabilities. We calculate deferred tax assets and liabilities using enacted laws and tax rates that will be in effect when we expect the differences to reverse and be applied to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred taxes of a change in tax rates is recognized in income in the period that includes the enactment date. Deferred tax assets are recognized for deductible temporary differences, net operating loss carryforwards, and credit carryforwards if it is more likely than not that the tax benefits will be realized. Deferred tax assets are not recorded, however, in the following circumstances:
	•	A deferred tax asset is not recorded for net operating loss carryforwards created by excess tax benefits from the exercise of stock options. To the extent such net operating loss carryforwards are utilized, we will increase stockholders’ equity. The historical and current deferred tax assets related to excess tax benefits from stock option exercises are excluded in the presentation of our financial results.
	•	Deferred tax assets are not recorded to the extent they are attributed to uncertain tax positions.
	For deferred tax assets that cannot be recognized under the more-likely-than-not-standard, we have established a valuation allowance. In the event we determine that we are able to realize our deferred tax assets in the future in excess of our net recorded amount, we would reverse the valuation allowance associated with such deferred tax assets in the period such determination was made. Also, if we determine that we are not able to realize all or part of our net deferred tax assets in the future, we would record a valuation allowance on such net deferred tax assets with a corresponding increase in expense in the period such determination was made.
Business Combinations	'				'
	Business Combinations
	For each business we acquire, the excess of the fair value of the consideration transferred over the fair value of the net tangible assets acquired and net tangible liabilities assumed was allocated to various identifiable intangible assets and goodwill. Identifiable intangible assets typically consist of purchased technology and customer-related intangibles, which are amortized to expense over their useful lives. Goodwill, representing the excess of the purchase consideration over the fair value of net tangible and identifiable intangible assets, is not amortized.
Derivative Financial Instruments	'				'
	Derivative Financial Instruments
	We are exposed to fluctuations in foreign currency exchange rates and have established a foreign currency hedging program to hedge certain foreign currency forecasted transactions and exposures from existing assets and liabilities. Our derivative instruments consist of foreign currency exchange contracts. By using derivative instruments, we subject ourselves to credit risk. If a counterparty fails to fulfill its performance obligations under a derivative contract, our credit risk will equal the fair value of the derivative instrument. Generally, when the fair value of our derivative contracts is a net asset, the counterparty owes us, thus creating a receivable risk. We minimize counterparty credit risk by entering into derivative transactions with major financial institutions and, as such, we do not expect material losses as a result of default by our counterparties. We execute foreign currency transactions in exchange-traded or over-the-counter markets for which quoted prices exist. We do not hold or issue derivative financial instruments for speculative or trading purposes.
	To manage the foreign currency volatility, we aggregate exposures on a consolidated basis to take advantage of natural offsets. The primary exposures are the Japanese yen, where we are in a long position, and the euro and the British pound, where we are in a short position. Most large European revenue contracts are denominated and paid to us in U.S. dollars while our European expenses, including substantial research and development operations, are paid in local currencies causing a short position in the euro and the British pound. In addition, we experience greater inflows than outflows of Japanese yen as almost all Japanese-based customers contract and pay us in Japanese yen. While these exposures are aggregated on a consolidated basis to take advantage of natural offsets, substantial exposures remain.
	To partially offset the net exposures in the euro, British pound, and the Japanese yen, we enter into foreign currency exchange contracts of less than one year which are designated as cash flow hedges. Any gain or loss on Japanese yen contracts is classified as product revenue when the hedged transaction occurs while any gain or loss on euro and British pound contracts is classified as operating expense when the hedged transaction occurs.
	We use an income approach to determine the fair value of our foreign currency contracts and record them at fair value utilizing observable market inputs at the measurement date. We report the fair value of derivatives in other receivables, if the balance is an asset, or accrued liabilities, if the balance is a liability, in the consolidated balance sheet. The accounting for changes in the fair value of a derivative depends upon whether it has been designated in a hedging relationship and on the type of hedging relationship. To qualify for designation in a hedging relationship, specific criteria must be met and the appropriate documentation maintained. Hedging relationships, if designated, are established pursuant to our risk management policy and are initially and regularly evaluated to determine whether they are expected to be, and have been, highly effective hedges. We formally document all relationships between foreign currency exchange contracts and hedged items as well as our risk management objectives and strategies for undertaking various hedge transactions.
	All hedges designated as cash flow hedges are linked to forecasted transactions and we assess, both at inception of the hedge and on an ongoing basis, the effectiveness of the foreign currency exchange contracts in offsetting changes in the cash flows of the hedged items. We report the effective portions of the net gains or losses on these foreign currency exchange contracts as a component of accumulated other comprehensive income in stockholders’ equity. Accumulated other comprehensive income associated with hedges of forecasted transactions is reclassified to the consolidated statement of income in the same period the forecasted transaction occurs or the hedge is no longer effective. We expect substantially all of the hedge balance in accumulated other comprehensive income to be reclassified to the consolidated statement of income within the next twelve months.
	We enter into foreign currency exchange contracts to offset the earnings impact relating to the variability in exchange rates on certain short-term monetary assets and liabilities denominated in non-functional currencies. We do not designate these foreign currency contracts as hedges. The change in fair value of these derivative instruments not designated as hedging instruments is reported each period in other income (expense), net, in our consolidated statement of income.
Revenue Recognition	'				'
	Revenue Recognition
	We report revenue in two categories based on how revenue is generated: (i) system and software and (ii) service and support.
	System and software revenues – We derive system and software revenues from the sale of licenses of software products, emulation hardware systems, and finance fee revenues from our long-term installment receivables resulting from product sales. We primarily license our products using two different license types:
	1.Term licenses – We use this license type primarily for software sales. This license type provides the customer with the right to use a fixed list of software products for a specified time period, typically three years, with payments spread over the license term, and does not provide the customer with the right to use the products after the end of the term. Term license arrangements may allow the customer to share products between multiple locations and remix product usage from the fixed list of products at regular intervals during the license term. We generally recognize product revenue from term license arrangements upon product delivery and start of the license term. In a term license agreement where we provide the customer with rights to unspecified or unreleased future products, we recognize revenue ratably over the license term.
	2.Perpetual licenses – We use this license type for software and emulation hardware system sales. This license type provides the customer with the right to use the product in perpetuity and typically does not provide for extended payment terms. We generally recognize product revenue from perpetual license arrangements upon product delivery assuming all other criteria for revenue recognition have been met.
	We include finance fee revenues from the accretion of the discount on long-term installment receivables in system and software revenues. Finance fee revenues were approximately 2.0% of total revenues for fiscal 2014, 2013, and 2012.
	Service and support revenues – We derive service and support revenues from software and hardware post-contract maintenance or support services and professional services, which include consulting, training, and other services. We recognize revenue ratably over the support services term. We record professional service revenue as the services are provided to the customer.
	We determine whether product revenue recognition is appropriate based upon the evaluation of whether the following four criteria have been met:
	1.Persuasive evidence of an arrangement exists – Generally, we use either a customer signed contract or qualified customer purchase order as evidence of an arrangement for both term and perpetual licenses. For professional service engagements, we generally use a signed professional services agreement and a statement of work to evidence an arrangement. Sales through our distributors are evidenced by an agreement governing the relationship, together with binding purchase orders from the distributor on a transaction-by-transaction basis.
	2.Delivery has occurred – We generally deliver software and the corresponding access keys to customers electronically. Electronic delivery occurs when we provide the customer access to the software. We may also deliver the software on a compact disc. With respect to emulation hardware systems, we transfer title to the customer upon shipment. Our software license and emulation hardware system agreements generally do not contain conditions for acceptance.
	3.Fee is fixed or determinable – We assess whether a fee is fixed or determinable at the outset of the arrangement, primarily based on the payment terms associated with the transaction. We have established a history of collecting under the original contract with installment terms without providing concessions on payments, products, or services. Additionally, for installment contracts, we determine that the fee is fixed or determinable if the arrangement has a payment schedule that is within the term of the licenses and the payments are collected in equal or nearly equal installments, when evaluated on a cumulative basis. If the fee is not deemed to be fixed or determinable, we recognize revenue as payments become due and payable.
	Significant judgment is involved in assessing whether a fee is fixed or determinable. We must also make these judgments when assessing whether a contract amendment to a term arrangement (primarily in the context of a license extension or renewal) constitutes a concession. Our experience has been that we are able to determine whether a fee is fixed or determinable for term licenses. If we no longer were to have a history of collecting under the original contract without providing concessions on term licenses, revenue from term licenses would be required to be recognized when payments under the installment contract become due and payable. Such a change could have a material impact on our results of operations.
	4.Collectibility is probable – To recognize revenue, we must judge collectibility of the arrangement fees on a customer-by-customer basis pursuant to our credit review process. We typically sell to customers with whom there is a history of successful collection. We evaluate the financial position and a customer’s ability to pay whenever an existing customer purchases new products, renews an existing arrangement, or requests an increase in credit terms. For certain industries for which our products are not considered core to the industry or the industry is generally considered troubled, we impose higher credit standards. If we determine that collectibility is not probable based upon our credit review process or the customer’s payment history, we recognize revenue as payments are received.
	Multiple element arrangements involving software licenses – For multiple element arrangements involving software and other software-related deliverables, vendor-specific objective evidence of fair value (VSOE) must exist to allocate the total fee among all delivered and non-essential undelivered elements of the arrangement. If undelivered elements of the arrangement are essential to the functionality of the product, we defer revenue until the essential elements are delivered. If VSOE does not exist for one or more non-essential undelivered elements, we defer revenue until such evidence exists for the undelivered elements, or until all elements are delivered, whichever is earlier. If VSOE of all non-essential undelivered elements exists but VSOE does not exist for one or more delivered elements, we recognize revenue using the residual method. Under the residual method, we defer revenue related to the undelivered elements based upon VSOE and we recognize the remaining portion of the arrangement fee as revenue for the delivered elements, assuming all other criteria for revenue recognition are met.
	We base our VSOE for certain elements of an arrangement upon the pricing in comparable transactions when the element is sold separately. We primarily base our VSOE for term and perpetual support services upon customer renewal history where the services are sold separately. We also base VSOE for professional services and installation services for emulation hardware systems upon the price charged when the services are sold separately.
	Multiple element arrangements involving hardware – For multiple element arrangements involving our emulation hardware systems, we allocate revenue to each element based on the relative selling price of each deliverable. In order to meet the separation criteria to allocate revenue to each element we must determine the standalone selling price of each element using a hierarchy of evidence.
	The authoritative guidance requires that, in the absence of VSOE or third-party evidence (TPE), a company must develop an estimated selling price (ESP). ESP is defined as the price at which the vendor would transact if the deliverable was sold by the vendor regularly on a standalone basis. A company should consider market conditions as well as entity-specific factors when estimating a selling price.We base our ESP for certain elements in arrangements on either costs incurred to manufacture a product plus a reasonable profit margin or standalone sales to similar customers. In determining profit margins, we consider current market conditions, pricing strategies related to the class of customer, and the level of penetration we have with the customer. In other cases, we may have limited sales on a standalone basis to the same or similar customers and/or guaranteed pricing on future purchases of the same item.
Software Development Costs	'				'
	Software Development Costs
	We capitalize software development costs beginning when a product’s technological feasibility has been established by either completion of a detail program design or completion of a working model of the product and ending when a product is available for general release to customers. The period between the achievement of technological feasibility and the general release of our products has historically been of short duration. As a result, such capitalizable software development costs were insignificant and have been charged to research and development expense in all periods in the accompanying consolidated statements of income.
	We capitalized $3,698 of acquired developed technology during fiscal 2014. We did not capitalize any acquired developed technology during fiscal 2013 or 2012.
Advertising Costs	'				'
	Advertising Costs
	We expense all advertising costs as incurred. Advertising expense is included in marketing and selling expense in the accompanying consolidated statement of income
Special Charges	'				'
	Special Charges
	We record restructuring charges within special charges in the consolidated statement of income in connection with our plans to better align our cost structure with projected operations in the future. Special charges primarily consist of costs incurred related to certain litigation, employee severance, acquisitions, excess facilities, and asset related charges.
	Employee severance and related costs include severance benefits, notice pay, and outplacement services. These rebalance charges generally represent the aggregate of numerous unrelated rebalance plans which impact several employee groups, none of which is individually material to our financial position or results of operations. We determine termination benefit amounts based on employee status, years of service, and local statutory requirements. We communicate termination benefits to the affected employees prior to the end of the quarter in which we record the charge.
Net Income Per Share	'				'
	Net Income Per Share
	We compute basic net income per share using the weighted average number of common shares outstanding during the period. We compute diluted net income per share using the weighted average number of common shares and potentially dilutive common shares outstanding during the period. Potentially dilutive common shares consist of restricted stock units, common shares issuable upon exercise of employee stock options, purchase rights from employee stock purchase plans, and common shares issuable upon conversion of the convertible subordinated debentures using the treasury stock method, if dilutive. Net income used to compute basic and diluted net income per share is reduced for the adjustment of the noncontrolling interest with redemption feature to its calculated redemption value at January 31, 2014. See additional discussion in Note 11. “Net Income Per Share.”
Accounting for Stock-based Compensation	'				'
	Accounting for Stock-Based Compensation
	We measure stock-based compensation cost at the grant date, based on the fair value of the award, and recognize the expense on a straight-line basis over the employee’s requisite service period. For options and stock awards that vest fully on any termination of service, there is no requisite service period and consequently we recognize the expense fully in the period in which the award is granted. We present the excess tax benefit from the exercise of stock options when the benefit that was previously recorded as a financing activity in the consolidated statements of cash flows is utilized.
	We have elected to compute the timing of excess tax benefits from the exercise of stock options on the “with-and-without” approach. Under this approach, we will not record an excess tax benefit until such time as a cash tax benefit is recognized. Further, we will include the impact of these excess tax benefits in the calculation of indirect tax attributes, such as the research and development credit and the domestic manufacturing deduction. We will compute the pool of excess tax benefits available to offset any future shortfalls in the tax benefits actually realized on exercises of stock options as a single pool for employees and non-employees.
	See a further description of how we estimate the fair value of stock options and purchase rights under our employee stock purchase plans (ESPPs) in Note 9. “Employee Stock and Savings Plans and Stockholders' Equity.”
Transfers of Financial Assets	'				'
	Transfer of Financial Assets
	We finance certain software license agreements with customers through the sale, assignment, and transfer of the future payments under those agreements to financing institutions on a non-recourse basis. We retain no interest in the transferred receivable. We record such transfers as sales of the related accounts receivable when we are considered to have surrendered control of such receivables. The gain or loss on the sale of receivables is included in general and administration in operating expenses in our consolidated statement of income. The gain or loss on the sale of receivables consists of two components: (i) the discount on sold receivables, which is the difference between the undiscounted balance of the receivables, and the net proceeds received from the financing institution and (ii) the unaccreted interest on the receivables sold. We impute interest on the receivables based on prevailing market rates and record this as a discount against the receivable.
Reclassification	'				'
					Reclassifications
					Certain items have been reclassified within operating expenses for fiscal 2013. We have reclassified certain litigation costs out of general and administration into special charges, related to patent litigation involving Emulation and Verification Engineering S.A. and EVE-USA, Inc. (together EVE), Synopsys, Inc. (Synopsys), and us regarding emulation technology. These litigation costs are included in special charges because of their unusual nature due to the significance in variability of timing and amount. These reclassifications had no impact on total operating expenses, operating income, or net income. See further discussion of these lawsuits in Note 8. "Commitments and Contingencies."

Fair_Value_Measurement_Fair_Va

Fair Value Measurement Fair Value Measurement (Policies)	12 Months Ended
	Jan. 31, 2014
Fair Value Disclosures [Abstract]	'
Fair Value of Financial Instruments	'
	The Financial Accounting Standards Board's authoritative guidance for the hierarchy of valuation techniques is based on whether the inputs to those valuation techniques are observable or unobservable. Observable inputs reflect market data obtained from independent sources. Unobservable inputs reflect our market assumptions. The fair value hierarchy consists of the following three levels:
	•	Level 1—Quoted prices for identical instruments in active markets;
	•	Level 2—Quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model-derived valuations whose significant inputs are observable; and
	•	Level 3—One or more significant inputs to the valuation model are unobservable.
Short-Term Investments Fair Value Determination	'
	We based the fair value of bank certificates of deposit included in short-term investments on quoted market prices for similar instruments in markets that are not active (Level 2).
Contingent Consideration	'
	In connection with certain acquisitions, payment of a portion of the purchase price is contingent typically upon the acquired business’ achievement of certain revenue goals. As of January 31, 2014, of the total recorded balance, $1,565 was included in accrued and other liabilities and $3,006 was included in other long-term liabilities on our consolidated balance sheet. As of January 31, 2013, of the total recorded balance, $1,197 was included in accrued and other liabilities and $4,819 was included in other long-term liabilities on our consolidated balance sheet.
	We have estimated the fair value of our contingent consideration as the present value of the expected payments over the term of the arrangements.
Notes Payable Fair Value Determination	'
	We based the fair value of notes payable on the quoted market price at the balance sheet date. The quoted market price for our notes is derived from observable inputs including our stock price, stock volatility, and interest rate (Level 2).

Term_Receivable_and_Trade_Acco1

Term Receivable and Trade Accounts Receivable Balances Term Receivable and Trade Accounts Receivable (Policies)	12 Months Ended
	Jan. 31, 2014
Receivables [Abstract]	'
Receivables	'
	We have long-term installment receivables that are attributable to multi-year, multi-element term license sales agreements. We include balances under term agreements that are due within one year in trade accounts receivable, net and balances that are due more than one year from the balance sheet date in term receivables, long-term. We discount the total product portion of the agreements to reflect the interest component of the transaction. We amortize the interest component of the transaction, using the effective interest method, to system and software revenues over the period in which payments are made and balances are outstanding. We determine the discount rate at the outset of the arrangement based upon the current credit rating of the customer. We reset the discount rate periodically considering changes in prevailing interest rates but do not adjust previously discounted balances.
Trade and Other Accounts Receivable, Unbilled	'
	Trade accounts receivable include billed amounts whereas term receivables, short-term is comprised of unbilled amounts. Term receivables, short term represent the portion of long-term installment agreements that are due within one year. Billings for term agreements typically occur thirty days prior to the contractual due date, in accordance with individual contract installment terms. Term receivables, long-term represent unbilled amounts which are scheduled to be collected beyond one year.
Financing Receivable Credit Quality	'
	We perform a credit risk assessment of all customers using the Standard & Poor’s (S&P) credit rating as our primary credit-quality indicator. The S&P credit ratings are based on the most recent S&P score available. For customers that do not have an S&P credit rating, we base our credit risk assessment on an internal credit assessment which is based on selected short-term financial ratios. Our internal credit assessment is based upon results provided in the customer's most recent financial statements.
Allowance For Uncollectible Accounts Receivable	'
	We maintain allowances for doubtful accounts on trade accounts receivable and term receivables, long-term for estimated losses resulting from the inability of our customers to make required payments. We regularly evaluate the collectibility of our trade accounts receivable based on a combination of factors. When we become aware of a specific customer’s inability to meet its financial obligations, such as in the case of bankruptcy or deterioration in the customer’s operating results, financial position, or credit rating, we record a specific reserve for bad debt to reduce the related receivable to the amount believed to be collectible. We also record unspecified reserves for bad debt for all other customers based on a variety of factors including length of time the receivables are past due, the financial health of the customers, the current business environment, and historical experience. Current economic conditions we have considered include forecasted spending in the semiconductor industry, consumer spending for electronics, integrated circuit research and development spending, and volatility in gross domestic product. If these factors change or circumstances related to specific customers change, we adjust the estimates of the recoverability of receivables resulting in either additional selling expense or a reduction in selling expense in the period the determination is made.

Special_Charges_Costs_associat

Special Charges Costs associated with exit or disposal activities or restructuring (Policies)	12 Months Ended
	Jan. 31, 2014
Restructuring and Related Activities [Abstract]	'
Costs Associated with Exit or Disposal Activities or Restructurings	'
	Special Charges
	We record restructuring charges within special charges in the consolidated statement of income in connection with our plans to better align our cost structure with projected operations in the future. Special charges primarily consist of costs incurred related to certain litigation, employee severance, acquisitions, excess facilities, and asset related charges.
	Employee severance and related costs include severance benefits, notice pay, and outplacement services. These rebalance charges generally represent the aggregate of numerous unrelated rebalance plans which impact several employee groups, none of which is individually material to our financial position or results of operations. We determine termination benefit amounts based on employee status, years of service, and local statutory requirements. We communicate termination benefits to the affected employees prior to the end of the quarter in which we record the charge.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Jan. 31, 2014										Jan. 31, 2013
Accounting Policies [Abstract]	'										'
Schedule of Property Plant and Equipment Useful Lives	'										'
		Estimated Useful Lives (in years)
	Buildings		40
	Land improvements		20
	Computer equipment and furniture	3	-	5
	Leasehold improvements(1)	3	-	10
Property, Plant, and Equipment	'										'
	A summary of property, plant, and equipment, net is as follows:
	As of January 31,	2014			2013
	Computer equipment and furniture	$	319,698		$	308,229
	Buildings and building equipment	101,073			97,989
	Land and improvements	21,321			21,345
	Leasehold improvements	38,900			35,753
	Property, plant, and equipment, gross	480,992			463,316
	Less: accumulated depreciation and amortization	(320,827		)	(300,914		)
	Property, plant, and equipment, net	$	160,165		$	162,402
Schedule Of Purchased Technology and Other Intangible Asset Amortization Expense	'										'
	Total purchased technology and other intangible asset amortization expenses were as follows:
	Year ended January 31,	2014			2013			2012
	Purchased technology and other intangible asset amortization expenses	$	9,828		$	13,716		$	15,701
Schedule of Goodwill and Intangible Assets	'										'
	As of January 31, 2014, the carrying value of goodwill and intangible assets was as follows:
	As of January 31,	2014			2013
	Goodwill	$	549,044		$	535,932
	Net purchased technology and in-process research and development(1)	$	11,210		$	8,019
	Net other intangible assets(2)	$	11,589		$	13,819
Schedule of Goodwill Activity	'										'
	The following table summarizes goodwill activity:
	Balance as of January 31, 2012	$	527,102
	Acquisitions	8,437
	Earnouts	370
	Foreign exchange	23
	Balance as of January 31, 2013	$	535,932
	Acquisitions	12,545
	Earnouts	288
	Foreign exchange	279
	Balance as of January 31, 2014	$	549,044
Schedule of Expected Amortization Expense	'										'
	We estimate the aggregate amortization expense related to purchased technology and other intangible assets will be as follows:
	Fiscal years ending January 31,
	2015	$	9,402
	2016	6,516
	2017	3,401
	2018	2,361
	2019	1,071
	Thereafter	48
	Aggregate amortization expense	$	22,799
Advertising Expense	'										'
	Advertising expense is included in marketing and selling expense in the accompanying consolidated statement of income and was as follows:
	Year ended January 31,	2014			2013			2012
	Advertising expense	$	2,654		$	2,326		$	3,015
Sale Of Receivables	'										'
	We sold the following receivables to financing institutions on a non-recourse basis and recognized the following gain on the sale of those receivables:
	Year ended January 31,	2014			2013			2012
	Trade receivables, short-term	$	11,705		$	9,617		$	13,645
	Term receivables, long-term	11,912			11,094			16,662
	Total receivables sold	23,617			20,711			30,307
	Net proceeds	22,943			20,198			29,146
	Discount on sold receivables	(674		)	(513		)	(1,161		)
	Unaccreted interest on sold receivables	890			568			1,273
	Gain on sale of receivables	$	216		$	55		$	112
Schedule of Reclassification	'										'
											The reclassification of our previously issued fiscal 2013 consolidated statement of operations was made to conform to the current period presentation. The amounts have been reclassified as follows:
												Year ended January 31, 2013
												As Originally Reported		As Reclassified
											General and administration	$	74,324	$	70,692
											Special charges	$	6,314	$	9,946

Fair_Value_Measurement_Tables

Fair Value Measurement (Tables)	12 Months Ended
	Jan. 31, 2014
Fair Value Disclosures [Abstract]	'
Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis	'
	The following table presents information about financial assets and liabilities measured at fair value on a recurring basis as of January 31, 2014:
		Fair Value				Level 1		Level 2		Level 3
	Bank certificates of deposit	$	3,990			$	—	$	3,990	$	—
	Contingent consideration	$	(4,571	)		$	—	$	—	$	(4,571	)
	Total	$	(581	)		$	—	$	3,990	$	(4,571	)
	The following table presents information about financial assets and liabilities measured at fair value on a recurring basis as of January 31, 2013:
		Fair Value				Level 1		Level 2		Level 3
	Contingent consideration	$	(6,016	)		$	—	$	—	$	(6,016	)
Significant Unobservable Input	'
	The fair value measurement of our contingent consideration as of January 31, 2014 encompasses the following significant unobservable inputs:
	Unobservable Inputs		Range
	Total estimated contingent consideration		$0	-	$5,351
	Discount rate		9.50%	-	16.00%
	Timing of cash flows (in years)		0	-	4
Summary of Level 3 Activity	'
	The following table summarizes contingent consideration activity:
	Balance as of January 31, 2012	$	6,120
	New contingent consideration	1,208
	Payments	(1,504		)
	Adjustments	(42		)
	Interest accretion	234
	Balance as of January 31, 2013	$	6,016
	New contingent consideration	540
	Payments	(1,266		)
	Adjustments	(898		)
	Interest accretion	179
	Balance as of January 31, 2014	$	4,571
Schedule of Notes Payable	'
	The following table summarizes the fair value and carrying value of notes payable:
	As of January 31,	2014				2013
	Fair value of notes payable	$	306,535			$	293,867
	Carrying value of notes payable	$	224,261			$	218,546

Term_Receivable_and_Trade_Acco2

Term Receivable and Trade Accounts Receivable Balances Term Receivables and Trade Accounts Receivable (Tables)	12 Months Ended
	Jan. 31, 2014
Term Receivables and Trade Accounts Receivable [Abstract]	'
Schedule of Term Receivable and Trade Accounts Receivable	'
	Term receivable and trade accounts receivable balances were as follows:
	As of January 31,	2014		2013
	Trade accounts receivable	$	179,830	$	178,351
	Term receivables, short-term	$	274,653	$	233,894
	Term receivables, long-term	$	270,365	$	250,497
Credit Quality Indicators	'
	The credit risk assessment for our long-term receivables was as follows:
	As of January 31,	2014		2013
	S&P credit rating:
	AAA+ through BBB-	$	180,113	$	133,773
	BB+ and lower	29,654		45,298
		209,767		179,071
	Internal credit assessment	60,598		71,426
	Total long-term term receivables	$	270,365	$	250,497
Change in Allowance for Doubtful Accounts	'
	The following shows the change in allowance for doubtful accounts for the years ended January 31, 2014, 2013, and 2012:
	Allowance for doubtful accounts	Beginning balance		Charged to		Other			Ending balance
				expense		changes(1)
	Year ended January 31, 2014	$	5,331	$	517	$	(379	)	$	5,469
	Year ended January 31, 2013	$	4,432	$	1,147	$	(248	)	$	5,331
	Year ended January 31, 2012	$	3,941	$	688	$	(197	)	$	4,432

Notes_Payable_Tables

Notes Payable (Tables)	12 Months Ended
	Jan. 31, 2014
Debt Instrument	'
Redemption Prices	'
	We may redeem some or all of the 4.00% Debentures for cash on or after April 5, 2016 at the following redemption prices expressed as a percentage of principal, plus any accrued and unpaid interest:
	Period	Redemption Price
	Beginning on April 5, 2016 and ending on March 31, 2017	101.143	%
	Beginning on April 1, 2017 and ending on March 31, 2018	100.571	%
	On April 1, 2018 and thereafter	100	%
Principal Amount, Unamortized Debt Premium (Discount), Net Carrying Amount of the Liability Component, and Carrying Amount of the Equity Component	'
	The principal amount, unamortized debt discount, net carrying amount of the liability component, and carrying amount of the equity component of the 4.00% Debentures are as follows:
	As of	31-Jan-14			31-Jan-13
	Principal amount	$	253,000		$	253,000
	Unamortized debt discount	(28,739		)	(34,454		)
	Net carrying amount of the liability component	$	224,261		$	218,546
	Equity component	$	43,930		$	43,930
4.00% Debentures due 2031	'
Debt Instrument	'
Recognized Amounts in Interest Expense in the Consolidated Statement of Operations	'
	We recognized the following amounts in interest expense in the consolidated statement of operations related to the 4.00% Debentures:
	Year ended January 31,	2014			2013			2012
	Interest expense at the contractual interest rate	$	10,120		$	10,120		$	8,349
	Amortization of debt discount	$	5,715		$	5,322		$	4,154
6.25 Debentures Due 2026	'
Debt Instrument	'
Recognized Amounts in Interest Expense in the Consolidated Statement of Operations	'
	We recognized the following amounts in interest expense in the consolidated statements of operations related to the 6.25% Debentures, issued 2006:
	Year ended January 31,	2014			2013			2012
	Interest expense at the contractual interest rate	$	—		$	—		$	2,900
	Amortization of debt discount	$	—		$	—		$	793

Commitments_and_Contingencies_

Commitments and Contingencies Commitment and Contingencies (Tables)	12 Months Ended
	Jan. 31, 2014
Schedule of Rent Expense	'
	Rent expense under operating leases was as follows:
	Year ended January 31,	2014		2013		2012
	Rent expense	$	27,240	$	26,597	$	27,535
Schedule of Future Minimum Rental Payments for Operating Leases	'
	Future minimum lease payments under all non-cancelable operating leases are approximately as follows:
	Fiscal years ending January 31,	Lease
		Payments
	2015	$	23,117
	2016	18,372
	2017	11,927
	2018	6,601
	2019	3,343
	Thereafter	6,907
	Total	$	70,267

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Jan. 31, 2014
Income Tax Disclosure [Abstract]	'
Schedule of Income before Income Tax, Domestic and Foreign	'
	Domestic and foreign pre-tax income (loss) was as follows:
	Year ended January 31,	2014			2013			2012
	Domestic	$	(754	)	$	9,670		$	(62,943	)
	Foreign	163,822			131,665			145,267
	Total pre-tax income	$	163,068		$	141,335		$	82,324
Schedule of Components of Income Tax Expense (Benefit)	'
	The provision (benefit) for income taxes was as follows:
	Year ended January 31,	2014			2013			2012
	Current:
	Federal	$	(366	)	$	(210	)	$	475
	State	355			(65		)	137
	Foreign	6,585			4,964			(2,731		)
	Total current	6,574			4,689			(2,119		)
	Deferred:
	Federal and state	1,333			350			695
	Foreign	1,603			(2,338		)	361
	Total deferred	2,936			(1,988		)	1,056
	Total provision (benefit) for income taxes	$	9,510		$	2,701		$	(1,063	)
Provision for Income Taxes	'
	Year ended January 31,	2014			2013			2012
	Federal tax, at statutory rate	$	57,074		$	49,467		$	28,813
	State tax, net of federal benefit	355			(65		)	137
	Impact of international operations including withholding taxes and other reserves	(46,632		)	(50,275		)	(53,499		)
	Repatriation of foreign subsidiary earnings	20,367			12,661			1,364
	Foreign tax credits	(5,489		)	(8,203		)	(411		)
	Costs incurred for stock of acquired business	—			67			98
	Tax credits (excluding foreign tax credits)	(12,571		)	(11,782		)	(9,677		)
	Amortization of deferred charge	(2,311		)	—			323
	Change in valuation allowance	(5,929		)	5,978			28,275
	Stock-based compensation expense	2,593			1,895			2,947
	Non-deductible meals and entertainment	1,087			1,021			1,096
	Other, net	966			1,937			(529		)
	Provision (benefit) for income taxes	$	9,510		$	2,701		$	(1,063	)
Schedule of Deferred Tax Assets and Liabilities	'
	The tax effects of temporary differences and carryforwards, which gave rise to significant portions of deferred tax assets and liabilities, were as follows:
	As of January 31,	2014			2013
	Deferred tax assets:
	Depreciation of property, plant, and equipment	$	(8	)	$	274
	Reserves and allowances	10,733			10,398
	Accrued expenses not currently deductible	20,118			20,463
	Stock-based compensation expense	7,839			12,394
	Net operating loss carryforwards	40,245			55,612
	Tax credit carryforwards	90,852			75,639
	Purchased technology and other intangible assets	3,267			6,456
	Deferred revenue	3,680			3,097
	Other, net	4,844			7,853
	Total gross deferred tax assets	181,570			192,186
	Less valuation allowance	(126,989		)	(154,695		)
	Deferred tax assets	54,581			37,491
	Deferred tax liabilities:
	Intangible assets	(5,699		)	(8,286		)
	Undistributed foreign earnings	(32,132		)	(1,662		)
	Convertible debt	(11,276		)	(13,519		)
	Deferred tax liabilities	(49,107		)	(23,467		)
	Net deferred tax assets	$	5,474		$	14,024
Summary of Tax Credit Carryforwards	'
	As of January 31, 2014, we had the following foreign and U.S. Federal and state carryforwards for income tax purposes:
	Credit or carryforward	As of January 31,			Expiration
		2014
	Federal credits and carryforwards:
	Research and experimentation credit carryforward	$	70,201		Fiscal 2019 - 2034
	Net operating loss carryforward	$	179,123		Fiscal 2019 - 2032
	Foreign tax credits	$	14,335		Fiscal 2015 - 2024
	Alternative minimum tax credits	$	2,683		No expiration
	Childcare credits	$	1,649		Fiscal 2023 - 2034
	State income tax credits and carryforwards:
	Net operating loss carryforward	$	213,490		Fiscal 2015 - 2033
	Research and experimentation	$	18,026		Fiscal 2015 - 2029
	Miscellaneous	$	1,199		Various
	Foreign net operating loss carryforwards	$	34,122		Generally indefinite
Unrecognized Tax Position Reconciliation	'
	The below schedule shows the gross changes in unrecognized tax benefits associated with uncertain tax positions for the years ending January 31, 2014 and 2013:
	Unrecognized tax benefits as of January 31, 2012	$	41,905
	Gross increases—tax positions in prior period	457
	Gross decreases—tax positions in prior period	(7		)
	Gross increases—tax positions in current period	4,316
	Lapse of statute of limitations	(7,553		)
	Cumulative translation adjustment	(336		)
	Unrecognized tax benefits as of January 31, 2013	$	38,782
	Gross increases—tax positions in prior period	3,863
	Gross decreases—tax positions in prior period	(10,313		)
	Gross increases—tax positions in current period	3,900
	Gross decreases-tax positions current	—
	Settlements	(1,581		)
	Lapse of statute of limitations	(2,982		)
	Cumulative translation adjustment	(348		)
	Unrecognized tax benefits as of January 31, 2014	$	31,321

Employee_Stock_and_Savings_Pla1

Employee Stock and Savings Plans (Tables)	12 Months Ended
	Jan. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award	'
Proceeds From and Intrinsic Value of Options Exercised	'
	The total intrinsic value of options exercised and cash received from options exercised was as follows:
	Year ended January 31,	2014			2013				2012
	Intrinsic value	$	26,769		$	21,647			$	15,802
	Cash received	$	38,830		$	24,262			$	15,194
Schedule of Restricted Stock Activity	'
	The following table summarizes restricted stock activity (including the target number of shares awarded under performance-based restricted stock units):
		Restricted		Weighted				Weighted		Aggregate
		Stock Units		Average Grant				Average		Intrinsic
				Date Fair Value				Remaining		Value
								Contractual Term
								(Years)
	Nonvested as of January 31, 2013	3,996		$	13.39
	Granted	1,616		22.42
	Vested	(1,374	)	12.93
	Forfeited	(155	)	14.83
	Nonvested as of January 31, 2014	4,083		$	17.07			1.6		$	84,925
Schedule Of Fair Value Of Restricted Stock Units Vested	'
	The following table summarizes the fair value of restricted stock units vested:
	Year ended January 31,	2014			2013				2012
	Total fair value of restricted stock units vested	$	17,736		$	11,698			$	5,446
Schedule of Shares Issued Under Employee Stock Purchase Plans	'
	The following table summarizes shares issued under the ESPPs:
	Year ended January 31,	2014			2013				2012
	Shares issued under the ESPPs	1,554			1,884				2,099
	Cash received for the purchase of shares under the ESPPs	$	23,895		$	22,645			$	22,155
	Weighted average purchase price per share	$	15.38		$	12.02			$	10.55
Summary Of The Weighted Average Grant Date Fair Value	'
	The weighted average grant date fair values are summarized as follows:
	Year ended January 31,	2014			2013				2012
	Options granted	$	—		$	7.18			$	5.43
	Restricted stock units granted	$	22.42		$	16.74			$	10.91
	ESPP purchase rights	$	4.3		$	3.82			$	3.19
Schedule of Valuation Assumptions	'
	The fair value calculations used the following assumptions:
	Year ended January 31,	2014		2013			2012
	Stock Option Plans
	Risk-free interest rate	—		0.9% - 1.3%			1.2	%
	Dividend yield	—		0	%		0	%
	Expected life (in years)	—		5.8 - 6.3			6.3
	Volatility (range)	—		43% - 53%			53	%
	Volatility (weighted average)	—		43	%		53	%
Schedule of Employee Stock Purchase Plan Valuation Assumptions	'
	Year ended January 31,	2014		2013			2012
	Employee Stock Purchase Plans
	Risk-free interest rate	0.09% - 0.14%		0.05% - 0.15%			0.05% - 0.18%
	Dividend yield (range)	0% - 1%		0	%		0	%
	Dividend yield (weighted average)	0.5	%	0	%		0	%
	Expected life (in years)	0.5		0.5			0.5
	Volatility (range)	22% - 33%		33% - 43%			32% - 38%
	Volatility (weighted average)	29	%	39	%		35	%
Stock-Compensation Expense Recognized	'
	The following table summarizes stock-based compensation expense included in the results of operations and the tax benefit associated with the exercise of stock options:
	Year ended January 31,	2014			2013				2012
	Cost of revenues:
	Service and support	$	1,992		$	1,529			$	1,065
	Operating expense:
	Research and development	11,182			9,206				8,203
	Marketing and selling	7,777			6,654				5,874
	General and administration	8,399			6,308				6,516
	Equity plan-related compensation expense	$	29,350		$	23,697			$	21,658
	Tax effect of the exercise of stock options	$	386		$	266			$	—
Matching Contribution to Savings Plan	'
	Our matching contributions to the Savings Plan were as follows:
	Year ended January 31,	2014			2013				2012
	Employer matching contribution	$	7,708		$	7,181			$	7,141
Stock Options	'
Share-based Compensation Arrangement by Share-based Payment Award	'
Employee Stock and Savings Plans, Stock Options Activity	'
	Stock options outstanding, the weighted average exercise price, and transactions involving stock options are summarized as follows:
		Options		Weighted				Weighted		Aggregate
		Outstanding		Average				Average		Intrinsic
				Exercise				Remaining		Value
				Price				Contractual
								Terms
								(Years)
	Balance as of January 31, 2013	6,717		$	11.08
	Granted	—		—
	Exercised	(3,124	)	12.43
	Forfeited	3		4.2
	Expired	(9	)	12.37
	Balance as of January 31, 2014	3,587		9.87				5.38		$	39,195
	Options exercisable as of January 31, 2014	2,933		8.94				4.79		34,784
	Options vested as of January 31, 2014 and options expected to vest after January 31, 2014	3,587		$	9.87			5.38		$	39,195

Net_Income_Per_Share_Tables

Net Income Per Share (Tables)	12 Months Ended
	Jan. 31, 2014
Schedule of Earnings Per Share Basic and Diluted [Abstract]	'
Schedule of Earnings Per Share, Basic and Diluted	'
	The following provides the computation of basic and diluted net income per share:
	Year ended January 31,	2014			2013			2012
	Net income attributable to Mentor Graphics shareholders	$	155,258		$	138,736		$	83,872
	Noncontrolling interest adjustment to redemption value	(4,486		)	(5,272		)	—
	Adjusted net income attributable to Mentor Graphics shareholders	$	150,772		$	133,464		$	83,872
	Weighted average common shares used to calculate basic net income per share	113,671			110,998			110,138
	Employee stock options, restricted stock units and employee stock purchase plan	3,031			3,019			2,777
	Weighted average common and potential common shares used to calculate diluted net income per share	116,702			114,017			112,915
	Net income per share attributable to Mentor Graphics shareholders:
	Basic	$	1.33		$	1.2		$	0.76
	Diluted	$	1.29		$	1.17		$	0.74

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Income Accumulated Other Comprehensive Income (Tables)	12 Months Ended
	Jan. 31, 2014
Schedule of Accumulated Other Comprehensive Income (Loss)	'
	The following table summarizes the components of accumulated other comprehensive income, net of tax:
	As of January 31,	2014		2013
	Foreign currency translation adjustment	$	18,361	$	25,146
	Unrealized gain (loss) on derivatives	42		(12		)
	Pension liability	400		265
	Total accumulated other comprehensive income	$	18,803	$	25,399

Special_Charges_Tables

Special Charges (Tables)	12 Months Ended
	Jan. 31, 2014											Jan. 31, 2013											Jan. 31, 2012
Components Of Special Charges	'											'											'
	The following is a summary of the components of the special charges:
	Year ended January 31,	2014		2013		2012
	Litigation costs	$	11,597	$	3,632	$	—
	Employee severance and related costs	4,392		4,016		8,437
	Other	940		2,298		4,737
	Total special charges	$	16,929	$	9,946	$	13,174
Schedule Of Accrued Special Charges	'											'											'
	The following table shows changes in accrued special charges during the year ended January 31, 2014:											The following table shows changes in accrued special charges during the year ended January 31, 2013:											The following table shows changes in accrued special charges during the year ended January 31, 2012:
		Accrued special		Charges during		Payments during			Accrued special				Accrued special		Charges during		Payments during			Accrued special				Accrued special		Charges during		Payments during			Accrued special
		charges as of		the year ended		the year ended			charges as of				charges as of		the year ended		the year ended			charges as of				charges as of		the year ended		the year ended			charges as of
		31-Jan-13		31-Jan-14		31-Jan-14			31-Jan-14		(1)		31-Jan-12		31-Jan-13		31-Jan-13			31-Jan-13		(1)		31-Jan-11		31-Jan-12		31-Jan-12			31-Jan-12		(1)
	Litigation costs	$	624	$	11,597	$	(7,366	)	$	4,855		Litigation costs	$	—	$	3,632	$	(3,008	)	$	624		Employee severance and related costs	$	2,664	$	8,437	$	(7,433	)	$	3,668
	Employee severance and related costs	2,028		4,392		(5,416		)	1,004			Employee severance and related costs	3,668		4,016		(5,656		)	2,028			Other costs	4,266		4,737		(6,192		)	2,811
	Other costs	2,889		940		(1,842		)	1,987			Other costs	2,811		2,298		(2,220		)	2,889			Accrued special charges	$	6,930	$	13,174	$	(13,625	)	$	6,479
	Accrued special charges	$	5,541	$	16,929	$	(14,624	)	$	7,846		Accrued special charges	$	6,479	$	9,946	$	(10,884	)	$	5,541
																							(1)	Of the $6,479 total accrued special charges as of January 31, 2012, $2,173 represented the long-term portion, which primarily included accrued lease termination fees and other facility costs, net of sublease income. The remaining balance of $4,306 represented the short-term portion of accrued special charges.
	(1)	Of the $7,846 total accrued special charges as of January 31, 2014, $587 represented the long-term portion, which primarily included accrued lease termination fees and other facility costs, net of sublease income and other long-term costs. The remaining balance of $7,259 represented the short-term portion of accrued special charges.										(1)	Of the $5,541 total accrued special charges as of January 31, 2013, $2,213 represented the long-term portion, which primarily included accrued lease termination fees and other facility costs, net of sublease income. The remaining balance of $3,328 represented the short-term portion of accrued special charges.

Other_Income_Expense_Net_Table

Other Income (Expense), Net (Tables)	12 Months Ended
	Jan. 31, 2014
Component of Other Expense, Nonoperating	'
Other Income (Expense), Net	'
	Other income (expense), net was comprised of the following:
	Year ended January 31,	2014			2013			2012
	Interest income	$	2,360		$	1,944		$	2,195
	Foreign currency exchange loss	(1,872		)	(2,394		)	(718		)
	Gain on conversion of equity method investment to controlling interest	—			—			1,519
	Other, net	(1,008		)	(982		)	(1,420		)
	Other income (expense), net	$	(520	)	$	(1,432	)	$	1,576
	In fiscal 2012, we exchanged one of our product lines for a controlling interest in a privately-held company. Prior to acquiring this controlling interest, we had a noncontrolling interest, which was accounted for under the equity method of accounting. As a result of this transaction, we recognized a gain of $1,519 to adjust the carrying value of our equity method investment in the company to its fair value based on an income approach valuation method.

Related_Party_Transactions_Tab

Related Party Transactions (Tables)	12 Months Ended
	Jan. 31, 2014
Related Party Transactions [Abstract]	'
Revenue Recognized from Related Party	'
	The following table shows revenue recognized from these customers:
	Year ended January 31,	2014			2013			2012
	Revenue from customers	$	85,037		$	56,878		$	35,944
	Percentage of total revenues	7.4		%	5.2		%	3.5		%

Supplemental_Cash_Flow_Informa1

Supplemental Cash Flow Information Supplemental Cash Flow Detail (Tables)	12 Months Ended
	Jan. 31, 2014
Supplemental Cash Flow Elements [Abstract]	'
Schedule of Cash Flow, Supplemental Disclosures	'
	The following provides information concerning supplemental disclosures of cash flow activities:
	Year ended January 31,	2014		2013		2012
	Cash paid for:
	Interest	$	12,225	$	11,981	$	14,686
	Income taxes	$	11,871	$	10,777	$	8,707

Segment_Reporting_Tables

Segment Reporting (Tables)	12 Months Ended
	Jan. 31, 2014
Segment Reporting [Abstract]	'
Revenues Related to Operations in Geographic Regions	'
	Revenues and property, plant and equipment, net, related to operations in the geographic areas were:
	Year ended January 31,	2014		2013		2012
	Revenues:
	United States	$	497,954	$	467,595	$	397,801
	Other North America	15,250		13,544		18,361
	Total North America	513,204		481,139		416,162
	Europe	241,417		261,371		247,079
	Japan	113,796		127,789		116,469
	Pacific Rim	287,956		218,428		234,928
	Total revenues	$	1,156,373	$	1,088,727	$	1,014,638
Total Property, Plant, and Equipment, Net in Geographic Regions	'
	As of January 31,	2014		2013
	Property, plant, and equipment, net:
	United States	$	116,954	$	121,179
	Other North America	141		269
	Total North America	117,095		121,448
	Europe	34,800		33,029
	Japan	637		979
	Pacific Rim	7,633		6,946
	Total property, plant and equipment, net	$	160,165	$	162,402

Quarterly_Financial_Informatio1

Quarterly Financial Information - Unaudited (Tables)	12 Months Ended
	Jan. 31, 2014
Quarterly Financial Information Disclosure [Abstract]	'
Schedule of Quarterly Financial Information	'
	A summary of quarterly financial information follows:
	Quarter ended	April 30		July 31			October 31			January 31
	Fiscal 2014
	Total revenues	$	226,515	$	253,216		$	275,642		$	401,000
	Gross profit	$	186,334	$	208,359		$	229,570		$	345,003
	Operating income	$	5,893	$	26,578		$	33,372		$	117,197
	Net income attributable to Mentor Graphics shareholders	$	205	$	23,982		$	25,535		$	105,536
	Net income per share, basic (1)	$	0.01	$	0.19		$	0.21		$	0.91
	Net income per share, diluted (1)	$	0.01	$	0.19		$	0.2		$	0.89
	Fiscal 2013
	Total revenues	$	247,918	$	240,811		$	268,760		$	331,238
	Gross profit	$	202,535	$	194,235		$	218,497		$	283,770
	Operating income	$	32,822	$	19,907		$	37,809		$	71,095
	Net income attributable to Mentor Graphics shareholders	$	28,182	$	18,167		$	30,641		$	61,746
	Net income per share, basic (1)	$	0.26	$	0.17		$	0.27		$	0.5
	Net income per share, diluted (1)	$	0.25	$	0.16		$	0.27		$	0.49
	(1) We have adjusted the numerator of our earnings per share calculation by the following for the adjustment of our noncontrolling interest to the calculated redemption value, recorded directly to retained earnings:
	Quarter ended	30-Apr		31-Jul			31-Oct			31-Jan
	Fiscal 2014	$	468	$	(2,349	)	$	(2,032	)	$	(573	)
	Fiscal 2013	$	—	$	—		$	—		$	(5,272	)

Summary_of_Significant_Account3

Summary of Significant Accounting Policies Significant Accounting Policies - Additional Information (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Significant Accounting Policies	'	'	'
Number of businesses acquired	4	'	'
Finance fee percentage of revenue	2.00%	2.00%	2.00%
Capitalized acquired technology costs	$3,698	$0	$0
Building	'	'	'
Significant Accounting Policies	'	'	'
Property, plant and equipment, useful life	'40 years	'	'
Land Improvements	'	'	'
Significant Accounting Policies	'	'	'
Property, plant and equipment, useful life	'20 years	'	'
Equipment | Minimum	'	'	'
Significant Accounting Policies	'	'	'
Property, plant and equipment, useful life	'3 years	'	'
Equipment | Maximum	'	'	'
Significant Accounting Policies	'	'	'
Property, plant and equipment, useful life	'5 years	'	'
Leasehold Improvements | Minimum	'	'	'
Significant Accounting Policies	'	'	'
Property, plant and equipment, useful life	'3 years	'	'
Leasehold Improvements | Maximum	'	'	'
Significant Accounting Policies	'	'	'
Property, plant and equipment, useful life	'10 years	'	'
Purchased Technology | Minimum	'	'	'
Significant Accounting Policies	'	'	'
Finite-Lived intangible asset, useful life	'3 years	'	'
Purchased Technology | Maximum	'	'	'
Significant Accounting Policies	'	'	'
Finite-Lived intangible asset, useful life	'5 years	'	'
Other Intangible Assets | Minimum	'	'	'
Significant Accounting Policies	'	'	'
Finite-Lived intangible asset, useful life	'1 year	'	'
Other Intangible Assets | Maximum	'	'	'
Significant Accounting Policies	'	'	'
Finite-Lived intangible asset, useful life	'5 years	'	'
Frontline	'	'	'
Significant Accounting Policies	'	'	'
Equity method investment, ownership percentage	50.00%	'	'

Summary_of_Significant_Account4

Summary of Significant Accounting Policies Summary Of Property, Plant and Equipment, Net (Details) (USD $)	Jan. 31, 2014	Jan. 31, 2013
In Thousands, unless otherwise specified
Property, Plant and Equipment	'	'
Computer equipment and furniture	$319,698	$308,229
Buildings and building equipment	101,073	97,989
Land and improvements	21,321	21,345
Leasehold Improvements	38,900	35,753
Property, plant, and equipment, gross	480,992	463,316
Less accumulated depreciation and amortization	-320,827	-300,914
Property, plant, and equipment, net	$160,165	$162,402

Summary_of_Significant_Account5

Summary of Significant Accounting Policies Purchased Technology and Other Intangible Asset Amortization Expenses (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Schedule of Finite Lived Intangible Assets Amortization Expense	'	'	'
Amortization of intangible assets	$6,230	$5,915	$5,905
Purchased Technology and Other Intangible Asset	'	'	'
Schedule of Finite Lived Intangible Assets Amortization Expense	'	'	'
Amortization of intangible assets	$9,828	$13,716	$15,701

Summary_of_Significant_Account6

Summary of Significant Accounting Policies Carrying Value of Goodwill, Intangible Assets, and Long-lived Assets (Details) (USD $)	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
In Thousands, unless otherwise specified
Goodwill And Intangible Assets Disclosure	'	'	'
Goodwill	$549,044	$535,932	$527,102
Intangible assets, net	22,799	21,838	'
Purchased Technology and In-Process Research and Development	'	'	'
Goodwill And Intangible Assets Disclosure	'	'	'
Intangible assets, net	11,210	8,019	'
Other Intangible Assets	'	'	'
Goodwill And Intangible Assets Disclosure	'	'	'
Intangible assets, net	$11,589	$13,819	'

Summary_of_Significant_Account7

Summary of Significant Accounting Policies Carrying Value of Goodwill, Intangible Assets, and Long-lived Assets (Parenthetical) (Details) (USD $)	Jan. 31, 2014	Jan. 31, 2013
In Thousands, unless otherwise specified
Purchased Technology and In-Process Research and Development	'	'
Goodwill And Intangible Assets Disclosure	'	'
Intangible assets, accumulated amortization	$124,536	$121,011
Other Intangible Assets	'	'
Goodwill And Intangible Assets Disclosure	'	'
Intangible assets, accumulated amortization	$71,216	$65,049

Summary_of_Significant_Account8

Summary of Significant Accounting Policies Goodwill Activity (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014	Jan. 31, 2013
Goodwill	'	'
Goodwill, beginning balance	$535,932	$527,102
Acquisitions	12,545	8,437
Earnouts	288	370
Foreign exchange	279	23
Goodwill, ending balance	$549,044	$535,932

Summary_of_Significant_Account9

Summary of Significant Accounting Policies Aggregate Amortization Expense Related to Purchased Technology and Other Intangible Assets (Details) (Purchased Technology and Other Intangible Asset, USD $)	Jan. 31, 2014
In Thousands, unless otherwise specified
Purchased Technology and Other Intangible Asset	'
Goodwill And Intangible Assets Disclosure	'
Expected amortization expense, year 1	$9,402
Expected amortization expense, year 2	6,516
Expected amortization expense, year 3	3,401
Expected amortization expense, year 4	2,361
Expected amortization expense, year 5	1,071
Finite-lived intangible assets, amortization expense, thereafter	48
Finite lived intangible assets future amortization	$22,799

Recovered_Sheet1

Summary of Significant Accounting Policies Advertising Expense Included in Marketing and Selling (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Advertising Costs	'	'	'
Advertising expense	$2,654	$2,326	$3,015

Recovered_Sheet2

Summary of Significant Accounting Policies (Gain) Loss on the Sale of Trade Receivables (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Sale of Receivables	'	'	'
Total receivables sold	$23,617	$20,711	$30,307
Net proceeds	22,943	20,198	29,146
Discount on sold receivables	-674	-513	-1,161
Unaccreted interest on sold receivables	890	568	1,273
Gain on sale of accounts receivable	216	55	112
Trade accounts receivable	'	'	'
Sale of Receivables	'	'	'
Total receivables sold	11,705	9,617	13,645
Term Receivables Long Term	'	'	'
Sale of Receivables	'	'	'
Total receivables sold	$11,912	$11,094	$16,662

Recovered_Sheet3

Summary of Significant Accounting Policies Reclassification (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Reclassification	'	'	'
General and administration	$75,543	$70,692	$74,811
Special charges	16,929	9,946	13,174
Scenario, Previously Reported	'	'	'
Reclassification	'	'	'
General and administration	'	74,324	'
Special charges	'	$6,314	'

Fair_Value_Measurement_Financi

Fair Value Measurement Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) (USD $)	Jan. 31, 2014	Jan. 31, 2013
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Short-term investments	$3,990	$0
Fair Value, Measurements, Recurring	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Short-term investments	3,990	'
Contingent consideration	4,571	6,016
Assets and liabilities net fair value disclosure	-581	'
Level 1 | Fair Value, Measurements, Recurring	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Short-term investments	0	'
Contingent consideration	0	0
Assets and liabilities net fair value disclosure	0	'
Level 2 | Fair Value, Measurements, Recurring	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Short-term investments	3,990	'
Contingent consideration	0	0
Assets and liabilities net fair value disclosure	3,990	'
Level 3 | Fair Value, Measurements, Recurring	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Short-term investments	0	'
Contingent consideration	4,571	6,016
Assets and liabilities net fair value disclosure	($4,571)	'

Fair_Value_Measurement_Fair_Va1

Fair Value Measurement Fair Value Measurement Level 3 Unobservable Inputs (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014
Unobservable Inputs [Abstract]	'
Total estimated contingent consideration, low	$0
Total estimated contingent consideration, high	$5,351
Discount rate, low	9.50%
Discount rate, high	16.00%
Timing of cash flows (in years), low	0
Timing of cash flows (in years), high	4

Fair_Value_Measurement_Summary

Fair Value Measurement Summary of Level 3 Activity (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014	Jan. 31, 2013
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'
Balance at beginning of period	$6,016	$6,120
New contingent consideration	540	1,208
Payments	-1,266	-1,504
Adjustments	-898	-42
Interest accretion	179	234
Balance at end of period	$4,571	$6,016

Fair_Value_Measurement_Additio

Fair Value Measurement - Additional Information (Detail) (USD $)	Jan. 31, 2014	Jan. 31, 2013
Disclosure Fair Value Measurement Additional Information [Abstract]	'	'
Fair value of contingent consideration included in accrued liabilities	$1,565,000	$1,197,000
Fair value of contingent consideration included in other long term liabilities	3,006,000	4,819,000
Fair value of notes payable	306,535,000	293,867,000
Notes payable	224,261,000	218,546,000
Current portion of notes payable	$0	$0

Term_Receivable_and_Trade_Acco3

Term Receivable and Trade Accounts Receivable Balances (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011
Term Receivable and Trade Accounts Receivable	'	'	'	'
Trade and term receivables	$454,483	$412,245	'	'
Term receivables, long-term	270,365	250,497	'	'
Billing period	'30 days	'	'	'
Allowance for doubtful accounts receivable, current	5,469	5,331	4,432	3,941
Provision for doubtful accounts	517	1,147	688	'
Net other deductions recoveries	-379	-248	-197	'
Trade accounts receivable	'	'	'	'
Term Receivable and Trade Accounts Receivable	'	'	'	'
Trade and term receivables	179,830	178,351	'	'
Term Receivabes Current	'	'	'	'
Term Receivable and Trade Accounts Receivable	'	'	'	'
Trade and term receivables	274,653	233,894	'	'
External Credit Rating, Investment Grade	'	'	'	'
Term Receivable and Trade Accounts Receivable	'	'	'	'
Term receivables, long-term	180,113	133,773	'	'
External Credit Rating, Non Investment Grade	'	'	'	'
Term Receivable and Trade Accounts Receivable	'	'	'	'
Term receivables, long-term	29,654	45,298	'	'
External Credit Rating, Standard & Poor's	'	'	'	'
Term Receivable and Trade Accounts Receivable	'	'	'	'
Term receivables, long-term	209,767	179,071	'	'
Internal Credit Rating	'	'	'	'
Term Receivable and Trade Accounts Receivable	'	'	'	'
Term receivables, long-term	$60,598	$71,426	'	'

ShortTerm_Borrowings_Additiona

Short-Term Borrowings - Additional Information (Detail) (USD $)

Jan. 31, 2014

Jan. 31, 2013

Jan. 31, 2014

Jan. 31, 2014

Jan. 31, 2014

Jan. 31, 2014

Jan. 31, 2014

Jan. 31, 2014

Jan. 31, 2014

Jan. 31, 2014

Jan. 31, 2014

Jan. 31, 2014

In Thousands, unless otherwise specified

Revolving Credit Facility

Revolving Credit Facility

Maximum

Maximum

Minimum

Minimum

L I B O R

L I B O R

Base Rate

Base Rate

Revolving Credit Facility

Revolving Credit Facility

Revolving Credit Facility

Revolving Credit Facility

Maximum

Minimum

Maximum

Minimum

Revolving Credit Facility

Revolving Credit Facility

Revolving Credit Facility

Revolving Credit Facility

Line of Credit Facility

'

'

'

'

'

'

'

'

'

'

'

'

Expiration date

'

'

24-May-17

'

'

'

'

'

'

'

'

'

Maximum borrowing capacity

'

'

$125,000

$125,000

'

'

'

'

'

'

'

'

Basis spread on variable rate

'

'

'

'

'

'

'

'

2.50%

2.00%

1.50%

1.00%

Amount outstanding

0

0

'

'

'

'

'

'

'

'

'

'

Unused capacity, commitment fee percentage

'

'

'

'

0.40%

'

0.30%

'

'

'

'

'

Adjusted quick ratio

'

'

'

'

'

'

'

1

'

'

'

'

Leverage ratio

'

'

'

'

'

2

'

'

'

'

'

'

Senior leverage ratio

'

'

'

'

'

0.9

'

'

'

'

'

'

Percentage of net current account receivable included in cash and account receivable ratio

'

'

'

42.00%

'

'

'

'

'

'

'

'

Cash and accounts receivable ratio

'

'

'

'

'

'

'

1.25

'

'

'

'

Maximum amount available for dividends and stock repurchase dollar limit

'

'

'

$50,000

'

'

'

'

'

'

'

'

Maximum amount available for dividend distribution and stock repurchase percent of cumulative net income

'

'

'

70.00%

'

'

'

'

'

'

'

'

Notes_Payable_Redemption_Price

Notes Payable - Redemption Prices Expressed as a Percentage of Principal, Plus any Accrued and Unpaid Interest (Detail) (4.00% Debentures due 2031, Convertible Subordinated Debt)	12 Months Ended
	Jan. 31, 2014
Redemption Period Beginning on April 5, 2016 and ending on March 31, 2017	'
Debt Instrument	'
Debentures redemption price	101.14%
Redemption Period Beginning on April 1, 2017 and ending on March 31, 2018	'
Debt Instrument	'
Debentures redemption price	100.57%
Redepmption Period Beginning on April 1, 2018 and thereafter	'
Debt Instrument	'
Debentures redemption price	100.00%

Notes_Payable_Principal_Amount

Notes Payable - Principal Amount, Unamortized Debt Discount, Net Carrying Amount of the Liability Component, and Carrying Amount of the Equity Component of the 4.00% Debentures (Detail) (4.00% Debentures due 2031, USD $)	Jan. 31, 2014	Jan. 31, 2013
In Thousands, unless otherwise specified
4.00% Debentures due 2031	'	'
Debt Instrument	'	'
Principal amount	$253,000	$253,000
Unamortized debt discount	28,739	34,454
Net carrying amount of the liability component	224,261	218,546
Equity component	$43,930	$43,930

Notes_Payable_Recognized_Amoun

Notes Payable - Recognized Amounts in Interest Expense in the Condensed Consolidated Statement of Operations Related to the 4.00% Debentures (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Debt Instrument	'	'	'
Interest expense at the contractual interest rate	$19,452	$18,866	$31,444
4.00% Debentures due 2031	'	'	'
Debt Instrument	'	'	'
Interest expense at the contractual interest rate	10,120	10,120	8,349
Amortization of debt discount	$5,715	$5,322	$4,154

Notes_Payable_Notes_Payable_Re

Notes Payable Notes Payable - Recognized Amounts in Interest Expense in the Consolidated Statement of Operations Related to the 6.25% Debentures (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Debt Instrument	'	'	'
Interest expense at the contractual interest rate	$19,452	$18,866	$31,444
6.25% Debentures due 2026, issued 2006	'	'	'
Debt Instrument	'	'	'
Interest expense at the contractual interest rate	0	0	2,900
Amortization of debt discount	$0	$0	$793

Notes_Payable_Additional_Infor

Notes Payable - Additional Information (Detail) (USD $)

3 Months Ended

12 Months Ended

12 Months Ended

Jan. 31, 2014

Jan. 31, 2014

Jan. 31, 2013

Jan. 31, 2012

Jan. 31, 2014

Jan. 31, 2013

Jan. 31, 2012

Apr. 30, 2011

Jan. 31, 2012

Jan. 31, 2012

Jan. 31, 2012

Apr. 30, 2010

4.00% Debentures due 2031

4.00% Debentures due 2031

4.00% Debentures due 2031

4.00% Debentures due 2031

6.25% Debentures due 2026, issued 2006

6.25% Debentures due 2026, issued 2006

Term Loan due 2013

Term Loan due 2013

Convertible Subordinated Debt

Convertible Subordinated Debt

Convertible Subordinated Debt

Convertible Subordinated Debt

Convertible Subordinated Debt

Debt Instrument

'

'

'

'

'

'

'

'

'

'

'

'

Repayments of principal in next five years

$0

$0

'

'

'

'

'

'

'

'

'

'

Issued debt

'

'

'

'

'

'

'

253,000,000

'

'

'

20,000,000

Interest rate

'

'

'

'

'

'

'

4.00%

6.25%

'

'

'

Conversion rate

'

'

'

'

49.133

'

'

48.6902

'

'

'

'

Principal amount multiple

'

'

'

'

1,000

'

'

1,000

'

'

'

'

Conversion price

'

'

'

'

$20.35

'

'

$20.54

'

'

'

'

Total number of shares

'

'

'

'

12,431,000

'

'

'

'

'

'

'

Market price of common stock exceeding percent of the conversion price

'

'

'

'

120.00%

'

'

'

'

'

'

'

Conversion circumstance stock price

'

'

'

'

$24.42

'

'

'

'

'

'

'

Threshold trading days

'

'

'

'

20

'

'

'

'

'

'

'

Threshold consecutive trading days

'

'

'

'

'30 days

'

'

'

'

'

'

'

Market price of debentures declining to maximum percent of the value of the common stock

'

'

'

'

98.00%

'

'

'

'

'

'

'

If-converted value in excess of principal

5,565,000

'

'

'

'

'

'

'

'

'

'

'

Interest rate during period

'

'

'

'

7.25%

7.25%

7.25%

'

'

'

'

'

Extinguishment of debt, amount

'

'

'

'

'

'

'

'

'

196,509,000

18,500,000

'

Loss on early extinguishment of debt before tax

'

'

'

'

'

'

'

'

'

11,192,000

312,000

'

Write-off of net unamortized debt discount

'

'

'

'

'

'

'

'

'

6,190,000

'

'

Premium on redemption

'

0

0

3,518,000

'

'

'

'

'

3,518,000

'

'

Write-off of unamortized debt issuance costs

'

'

'

'

'

'

'

'

'

$1,484,000

'

'

Term loan original term

'

'

'

'

'

'

'

'

'

'

'3 years

'

Commitments_and_Contingencies_1

Commitments and Contingencies Rent Expense Under Operating Leases (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Operating Leased Assets	'	'	'
Rent Expense	$27,240	$26,597	$27,535

Income_Taxes_Domestic_and_Fore

Income Taxes Domestic and Foreign Pre-tax Income (Loss) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Schedule Of Components Of Income Before Income Tax Expense Benefit	'	'	'
Domestic	($754)	$9,670	($62,943)
Foreign	163,822	131,665	145,267
Total pre-tax income	$163,068	$141,335	$82,324

Commitments_and_Contingencies_2

Commitments and Contingencies Future Minimum Lease Payments Under all Non-cancelable Operating Leases (Details) (USD $)	Jan. 31, 2014
In Thousands, unless otherwise specified
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]	'
Future minimum payments due, next twelve months	$23,117
Future minimum payments, due in two years	18,372
Future minimum payments, due in three years	11,927
Future minimum payments, due in four years	6,601
Future minimum payments, due in five years	3,343
Future minimum payments, due thereafter	6,907
Future minimum payments due	$70,267

Income_Taxes_Provision_Benefit

Income Taxes (Provision) Benefit for Income Taxes (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Current Income Tax Expense (Benefit) [Abstract]	'	'	'
Federal	($366)	($210)	$475
State	355	-65	137
Foreign	6,585	4,964	-2,731
Total current	6,574	4,689	-2,119
Deferred Income Tax Expense (Benefit) [Abstract]	'	'	'
Federal and state	1,333	350	695
Foreign	1,603	-2,338	361
Total deferred	2,936	-1,988	1,056
Provision (benefit) for income taxes	$9,510	$2,701	($1,063)

Income_Taxes_Difference_of_Eff

Income Taxes Difference of Effective Tax Rate from Federal Tax Rate (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Reconciliation of Statutory Federal Tax Rate	'	'	'
Federal tax, at statutory rate	$57,074	$49,467	$28,813
State tax, net of federal benefit	355	-65	137
Impact of international operations including withholding taxes and other reserves	-46,632	-50,275	-53,499
Repatriation of foreign subsidiary earnings	20,367	12,661	1,364
Foreign tax credits	-5,489	-8,203	-411
Costs incurred for stock of acquired business	0	67	98
Tax credits (excluding foreign tax credits)	-12,571	-11,782	-9,677
Amortization of deferred charge	-2,311	0	323
Losses and tax credits for which no benefit has been realized	-5,929	5,978	28,275
Stock-based compensation expense	2,593	1,895	2,947
Non-deductible meals and entertainment	1,087	1,021	1,096
Other, net	966	1,937	-529
Provision (benefit) for income taxes	$9,510	$2,701	($1,063)

Income_Taxes_Tax_Effects_of_Te

Income Taxes Tax Effects of Temporary Differences and Carryforwards on Deferred Tax Assets and Liabilities (Details) (USD $)	Jan. 31, 2014	Jan. 31, 2013
In Thousands, unless otherwise specified
Deferred Tax Assets, Net [Abstract]	'	'
Depreciation of property, plant, and equipment	($8)	$274
Reserves and allowances	10,733	10,398
Accrued expenses not currently deductible	20,118	20,463
Stock-based compensation expense	7,839	12,394
Net operating loss carryforwards	40,245	55,612
Tax credit carryforwards	90,852	75,639
Purchased technology and other intangible assets	3,267	6,456
Deferred revenue	3,680	3,097
Other, net	4,844	7,853
Total gross deferred tax assets	181,570	192,186
Less valuation allowance	-126,989	-154,695
Deferred tax assets	54,581	37,491
Deferred Tax Liabilities, Net [Abstract]	'	'
Intangible assets	-5,699	-8,286
Undistributed foreign earnings	-32,132	-1,662
Convertible debt	11,276	13,519
Deferred tax liabilities	49,107	23,467
Net deferred tax assets	$5,474	$14,024

Income_Taxes_Foreign_and_US_Fe

Income Taxes Foreign and U.S. Federal and State Tax Carryforwards for Income Tax Purposes (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014
Operating Loss and Tax Credit Carry Forward	'
Foreign net operating loss carryforwards	34,122
Minimum	'
Operating Loss and Tax Credit Carry Forward	'
Expiration date of tax credit carryforwards	31-Jan-15
Maximum	'
Operating Loss and Tax Credit Carry Forward	'
Expiration date of tax credit carryforwards	31-Jan-29
Minimum	'
Operating Loss and Tax Credit Carry Forward	'
Expiration date of operating loss carryforwards	31-Jan-15
Maximum	'
Operating Loss and Tax Credit Carry Forward	'
Expiration date of operating loss carryforwards	31-Jan-33
Minimum	'
Operating Loss and Tax Credit Carry Forward	'
Expiration date of tax credit carryforwards	31-Jan-23
Maximum	'
Operating Loss and Tax Credit Carry Forward	'
Expiration date of tax credit carryforwards	31-Jan-34
Minimum	'
Operating Loss and Tax Credit Carry Forward	'
Expiration date of tax credit carryforwards	31-Jan-15
Maximum	'
Operating Loss and Tax Credit Carry Forward	'
Expiration date of tax credit carryforwards	31-Jan-24
Minimum	'
Operating Loss and Tax Credit Carry Forward	'
Expiration date of operating loss carryforwards	31-Jan-19
Maximum	'
Operating Loss and Tax Credit Carry Forward	'
Expiration date of operating loss carryforwards	31-Jan-32
Minimum	'
Operating Loss and Tax Credit Carry Forward	'
Expiration date of tax credit carryforwards	31-Jan-19
Maximum	'
Operating Loss and Tax Credit Carry Forward	'
Expiration date of tax credit carryforwards	31-Jan-34
Internal Revenue Service (IRS)	'
Operating Loss and Tax Credit Carry Forward	'
Research and experimentation credit carryforward	70,201
Net operating loss carryforward	179,123
Foreign tax credits	14,335
Alternative minimum tax credits	2,683
Miscellaneous	1,649
State and Local Jurisdiction	'
Operating Loss and Tax Credit Carry Forward	'
Research and experimentation credit carryforward	18,026
Net operating loss carryforward	213,490
Miscellaneous	1,199

Income_Taxes_Income_Taxes_Addi

Income Taxes Income Taxes - Additional Information (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Income Taxes	'	'	'
Deferred tax assets unrecognized tax benefits	$38,893	$32,794	'
Undistributed earnings of foreign subsidiaries	432,481	'	'
Possible change in unrecognized tax benefit, lower	0	'	'
Possible change in unrecognized tax benefit, upper	4,000	'	'
Income tax penalties and interest expense	-1,710	-297	-677
Income tax penalties and interest accrued	7,687	9,538	'
Unrecognized tax benefits that would impact effective tax rate	$18,674	'	'
Domestic Tax Authority	'	'	'
Income Taxes	'	'	'
Open tax year	'2011	'	'
Ireland	'	'	'
Income Taxes	'	'	'
Open tax year	'2010	'	'

Income_Taxes_Schedule_of_Chang

Income Taxes Schedule of Changes in Unrecognized Tax Position (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Unrecognized Tax Positions Reconciliation	'	'	'
Unrecognized tax benefits	$31,321	$38,782	$41,905
Gross increases-tax positions in prior period	3,863	457	'
Gross decreases-tax positions in prior period	-10,313	-7	'
Gross increases-tax positions in current period	3,900	4,316	'
Gross decreases-tax positions current	0	'	'
Settlements	-1,581	'	'
Lapse of statute of limitations	-2,982	-7,553	'
Unrecognized Tax Benefits, Decrease Resulting from Foreign Currency Translation	($348)	($336)	'

Employee_Stock_and_Savings_Pla2

Employee Stock and Savings Plans and Stockholders Equity Employee Stock and Savings Plans Additional Information (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014
Restricted Stock	'
Share-based Compensation Arrangement by Share-based Payment Award	'
Unrecognized compensation cost period of recognition	'1 year 5 months 21 days
Unrecognized compensation cost	$58,964
Stock Option	'
Share-based Compensation Arrangement by Share-based Payment Award	'
Award expiry period from date of grant	'10 years 0 months 0 days
Stock Options	'
Share-based Compensation Arrangement by Share-based Payment Award	'
Unrecognized compensation cost period of recognition	'1 year 0 months 25 days
Unrecognized compensation cost	$3,580
Omnibus Incentive Plan	'
Share-based Compensation Arrangement by Share-based Payment Award	'
Award requisite service period	'4 years 0 months 0 days
Number of shares available for grant under incentive plan	3,993
Defined Contribution Pension	'
Share-based Compensation Arrangement by Share-based Payment Award	'
Employer matching contribution percent	50.00%
Employer matching contribution, percent of employees' gross pay	6.00%
Plan vesting term	'5 years 0 months 0 days
Employers matching contribution, annual vesting percentage	20.00%
Description of defined contribution pension and other postretirement plans	'We have an employee savings plan (the Savings Plan) that qualifies as a deferred salary arrangement under SectionB 401(k) of the Internal Revenue Code. Under the Savings Plan, participating U.S. employees may defer a portion of their pretax earnings, up to the Internal Revenue Service annual contribution limit. We currently match 50% of eligible employee's contributions, up to a maximum of 6% of the employee's earnings. Employer matching contributions vest over five years, 20% for each year of service completed.
Employee Stock Purchase Plans	'
Share-based Compensation Arrangement by Share-based Payment Award	'
Maximum number of shares that may be purchased by eligible participants	6
Eligible employee stock purchase price	85.00%
Shares available for future purchase under ESPPs	2,547

Employee_Stock_and_Savings_Pla3

Employee Stock and Savings Plans and Stockholders Equity Summary Stock Option Activity (Details) (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jan. 31, 2014	Jan. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]	'	'
Stock options outstanding	3,587	6,717
Stock options granted	0	'
Stock options exercised	-3,124	'
Stock options forfeited	3	'
Stock options expired	-9	'
Stock options outstanding exercisable	2,933	'
Stock options vested and expected to vest	3,587	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]	'	'
Weighted average exercise price of stock options outstanding	$9.87	$11.08
Weighted average exercise price of stock options granted	$0	'
Weighted average exercise price of stock options exercised	$12.43	'
Weighted average exercise price of stock options forfeited	$4.20	'
Weighted average exercise price of stock options expired	$12.37	'
Weighted average exercise price of stock options exercisable	$8.94	'
Weighted average exercise price of stock options vested and expected to vest	$9.87	'
Share Based Compensation Arrangement By Share Based Payment Award Options Weighted Average Remaining Contractual Term [Abstract]	'	'
Weighted average remaining contractual term of stock options outstanding	'5 years 4 months 17 days	'
Weighted average remaining contractual term of stock options exercisable	'4 years 9 months 14 days	'
Weighted average remaining contractual term of stock options vested and expected to vest	'5 years 4 months 17 days	'
Share Based Compensation Arrangement By Share Based Payment Award Options Aggregate Intrinsic Value [Abstract]	'	'
Aggregate intrinsic value of stock options outstanding	$39,195	'
Aggregate intrinsic value of options exercisable	34,784	'
Aggregate intrinsic value of stock options vested and expected to vest	$39,195	'

Employee_Stock_and_Savings_Pla4

Employee Stock and Savings Plans and Stockholders Equity Total Intrinsic Value of Options Exercised and Cash Received from Options Exercised (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award	'	'	'
Intrinsic value of options exercised	$26,769	$21,647	$15,802
Proceeds from stock options exercised	$38,830	$24,262	$15,194

Employee_Stock_and_Savings_Pla5

Employee Stock and Savings Plans and Stockholders Equity Summary of Restricted Stock Activity (Details) (Restricted Stock Units (RSUs), USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Restricted Stock Units (RSUs)	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]	'	'	'
Nonvested restricted stock units	4,083	3,996	'
Nonvested restricted stock units granted in period	1,616	'	'
Nonvested restricted stock units vested in period	-1,374	'	'
Nonvested restricted stock units forfeited in period	-155	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]	'	'	'
Weighted average grant date fair value of nonvested restricted stock units	$17.07	$13.39	'
Weighted average grant date fair value	$22.42	$16.74	$10.91
Weighted average grant date fair value of nonvested restricted stock units vested in period	$12.93	'	'
Weighted average grant date fair value of nonvested restricted stock units forfeited in period	$14.83	'	'
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Weighted Average Contractual Term [Abstract]	'	'	'
Weighted average remaining contractual terms of nonvested restricted stock units	'1 year 7 months 6 days	'	'
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Aggregate Intrinsic Value [Abstract]	'	'	'
Aggregate intrinsic value of nonvested restricted stock units	$84,925	'	'

Employee_Stock_and_Savings_Pla6

Employee Stock and Savings Plans and Stockholders Equity Summary of Fair Value of Restricted Stock Vested (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Total fair value of restricted stock units vested	$17,736	$11,698	$5,446

Employee_Stock_and_Savings_Pla7

Employee Stock and Savings Plans and Stockholders Equity Summary of Shares Issued Under ESPPs (Details) (Employee Stock Purchase Plans, USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Employee Stock Purchase Plans	'	'	'
Employee Stock Purchase Plan	'	'	'
Shares issued under ESPPs	1,554	1,884	2,099
Cash received for the purchase of shares under the ESPPs	$23,895	$22,645	$22,155
Weighted average purchase price of shares issued under ESPPs	$0	$0	$0

Employee_Stock_and_Savings_Pla8

Employee Stock and Savings Plans and Stockholders Equity Weighting of elements included in volatility assumption (Details)	12 Months Ended
	Jan. 31, 2013
Common Stock	'
Weighting of elements used in determining volatility assumption	20.00%
Exchange Traded Options	'
Weighting of elements used in determining volatility assumption	15.00%
Common Stock	'
Weighting of elements used in determining volatility assumption	35.00%
Exchange Traded Options	'
Weighting of elements used in determining volatility assumption	30.00%

Employee_Stock_and_Savings_Pla9

Employee Stock and Savings Plans and Stockholders Equity Summary of Weighted Average Grant Date Fair Values (Details) (USD $)	12 Months Ended
	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Stock Options	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award	'	'	'
Weighted average grant date fair value of options granted	$0	$7.18	$5.43
Restricted Stock Units (RSUs)	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award	'	'	'
Weighted average grant date fair value	$22.42	$16.74	$10.91
Employee Stock Purchase Plan	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award	'	'	'
Weighted average grant date fair value	$4.30	$3.82	$3.19

Recovered_Sheet4

Employee Stock and Savings Plans and Stockholders Equity Fair Value Calculation Assumptions (Details)	12 Months Ended
	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Employee Stock Purchase Plan	'	'	'
Share based Compensation Arrangement by Share based Payment Award, Fair Value Assumptions, Method Used	'	'	'
Risk-free interest rate, minimum	0.09%	0.05%	0.05%
Risk-free interest rate, maximum	0.14%	0.15%	0.18%
Dividend yield	0.47%	0.00%	0.00%
Expected term	'0 years 6 months 0 days	'0 years 6 months 0 days	'0 years 6 months 0 days
Volatility, minimum	22.00%	33.00%	32.00%
Volatility, maximum	33.00%	43.00%	38.00%
Weighted average volatility rate	29.00%	39.00%	35.00%
Stock Options	'	'	'
Share based Compensation Arrangement by Share based Payment Award, Fair Value Assumptions, Method Used	'	'	'
Risk-free interest rate, minimum	'	0.90%	'
Risk-free interest rate, maximum	'	1.30%	'
Risk-free interest rate	'	'	1.20%
Dividend yield	'	0.00%	0.00%
Expected term	'	'	'6 years 3 months 18 days
Volatility, minimum	'	43.00%	'
Volatility, maximum	'	53.00%	'
Volatility	'	'	53.00%
Weighted average volatility rate	'	43.00%	53.00%
Minimum | Employee Stock Purchase Plan	'	'	'
Share based Compensation Arrangement by Share based Payment Award, Fair Value Assumptions, Method Used	'	'	'
Dividend yield	0.00%	'	'
Minimum | Stock Options	'	'	'
Share based Compensation Arrangement by Share based Payment Award, Fair Value Assumptions, Method Used	'	'	'
Expected term	'	'5 years 9 months 18 days	'
Maximum | Employee Stock Purchase Plan	'	'	'
Share based Compensation Arrangement by Share based Payment Award, Fair Value Assumptions, Method Used	'	'	'
Dividend yield	1.00%	'	'
Maximum | Stock Options	'	'	'
Share based Compensation Arrangement by Share based Payment Award, Fair Value Assumptions, Method Used	'	'	'
Expected term	'	'6 years 3 months 18 days	'

Recovered_Sheet5

Employee Stock and Savings Plans - Stock Compensation Expense Recognized (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Employee Service Share-based Compensation, Allocation of Recognized Period Costs	'	'	'
Equity plan-related compensation expense	$29,350	$23,697	$21,658
Tax effect of the exercise of stock options	386	266	0
Cost of goods sold	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs	'	'	'
Equity plan-related compensation expense	1,992	1,529	1,065
Research and development	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs	'	'	'
Equity plan-related compensation expense	11,182	9,206	8,203
Selling and marketing	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs	'	'	'
Equity plan-related compensation expense	7,777	6,654	5,874
General and administration	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs	'	'	'
Equity plan-related compensation expense	$8,399	$6,308	$6,516

Recovered_Sheet6

Employee Stock and Savings Plans and Stockholders Equity Matching Contributions to Savings Plans (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Disclosure Matching Contributions To Savings Plans	'	'	'
Employer matching contribution	$7,708	$7,181	$7,141

Recovered_Sheet7

Employee Stock and Savings Plans and Stockholders Equity Dividends (Details) (USD $)	3 Months Ended					12 Months Ended			0 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jan. 31, 2014	Oct. 31, 2013	Jul. 31, 2013	Apr. 30, 2013	Jul. 31, 2010	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012	Feb. 27, 2014
									Subsequent Event
Dividends Declared	'	'	'	'	'	'	'	'	'
Dividends declaration date	21-Nov-13	22-Aug-13	23-May-13	7-Mar-13	'	'	'	'	27-Feb-14
Record date for distribution of rights	10-Dec-13	10-Sep-13	10-Jun-13	22-Mar-13	6-Jul-10	'	'	'	10-Mar-14
Dividends payment date	2-Jan-14	30-Sep-13	1-Jul-13	10-Apr-13	'	'	'	'	31-Mar-14
Cash dividends declared per common share	$0.05	$0.05	$0.05	$0.05	'	$0.18	$0	$0	$0.05
Dividends paid	$5,159	$5,096	$5,079	$5,064	'	$20,398	$0	$0	'
Dividend per share, annual amount	'	'	'	$0.18	'	'	'	'	'

Incentive_Stock_Rights_Additio

Incentive Stock Rights - Additional Information (Detail) (USD $)	3 Months Ended						12 Months Ended
	Jan. 31, 2014	Oct. 31, 2013	Jul. 31, 2013	Apr. 30, 2013	Jan. 31, 2012	Jul. 31, 2010	Jan. 31, 2014	Jun. 24, 2010
Class of Stock	'	'	'	'	'	'	'	'
Incentive stock purchase right adoption date	'	'	'	'	'	24-Jun-10	'	'
Dividend distribution of rights declared for each outstanding share of common stock	'	'	'	'	'	'	'	1
Record date for distribution of rights	10-Dec-13	10-Sep-13	10-Jun-13	22-Mar-13	'	6-Jul-10	'	'
Incentive stock purchase right amendment date	'	'	28-Jun-13	'	23-Dec-11	'	'	'
Right issuable with each new share of common stock	1	'	'	'	'	'	1	'
Number of shares called by rights	'	'	'	'	'	'	'	0.0001
Incentive stock purchase price	$90	'	'	'	'	'	$90	'
Percentage of common stock acquired to initiate exercise of incentive stock rights, minimum	'	'	'	'	'	'	15.00%	'
Percentage of common stock acquired to initiate exercise of incentive stock rights certain passive institutional investors	'	'	'	'	'	'	20.00%	'
Percent of incentive stock right exercise price for value of the entity's common stock received upon exercise of incentive stock right	'	'	'	'	'	'	200.00%	'
Date on which rights expire	'	'	'	'	'	'	30-Jun-15	'
Rights redemption price	'	'	'	'	'	'	$0.00	'

Net_Income_Per_Share_Additiona

Net Income Per Share - Additional Information (Detail) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014	Oct. 31, 2013	Jul. 31, 2013	Apr. 30, 2013	Jan. 31, 2013	Oct. 31, 2012	Jul. 31, 2012	Apr. 30, 2012	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Undistributed earnings, diluted	'	'	'	'	'	'	'	'	$2,075	$2,075	$2,075
Antidilutive securities excluded from computation of earnings per share	'	'	'	'	'	'	'	'	1,195	1,975	4,056
Non-controlling interest adjustment to redemption value	-573	-2,032	-2,349	468	-5,272	0	0	0	-4,486	-5,272	0
Retained Earnings	'	'	'	'	'	'	'	'	'	'	'
Adjustment of noncontrolling interest to redemption value	'	'	'	'	'	'	'	'	($4,486)	($3,590)	($1,682)

Net_Income_Per_Share_Computati

Net Income Per Share - Computation of Basic and Diluted Net Income Per Share (Detail) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jan. 31, 2014	Oct. 31, 2013	Jul. 31, 2013	Apr. 30, 2013	Jan. 31, 2013	Oct. 31, 2012	Jul. 31, 2012	Apr. 30, 2012	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Disclosure Computation Of Basic And Diluted Net Loss Per Share [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Net income attributable to Mentor Graphics shareholders	$105,536	$25,535	$23,982	$205	$61,746	$30,641	$18,167	$28,182	$155,258	$138,736	$83,872
Non-controlling interest adjustment to redemption value	-573	-2,032	-2,349	468	-5,272	0	0	0	-4,486	-5,272	0
Net income (loss) net of adjustments to redemption value	'	'	'	'	'	'	'	'	$150,772	$133,464	$83,872
Weighted average common shares used to calculate basic net income per share (in shares)	'	'	'	'	'	'	'	'	113,671	110,998	110,138
Employee stock options, restricted stock units and employee stock purchase plan (in shares)	'	'	'	'	'	'	'	'	3,031	3,019	2,777
Weighted average common and potential common shares used to calculate diluted net income per share (in shares)	'	'	'	'	'	'	'	'	116,702	114,017	112,915
Basic net income per share attributable to Mentor Graphics shareholders (in dollars per share)	$0.91	$0.21	$0.19	$0.01	$0.50	$0.27	$0.17	$0.26	$1.33	$1.20	$0.76
Diluted net income per share attributable to Mentor graphics shareholders (in dollars per share)	$0.89	$0.20	$0.19	$0.01	$0.49	$0.27	$0.16	$0.25	$1.29	$1.17	$0.74

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Income Components of Accumulated Other Comprehensive Income (Details) (USD $)	Jan. 31, 2014	Jan. 31, 2013
In Thousands, unless otherwise specified
Accumulated Other Comprehensive Income (Loss)	'	'
Foreign currency translation adjustment	$18,361	$25,146
Unrealized gain (loss) on derivatives, net of tax	42	-12
Pension liability	400	265
Accumulated other comprehensive income	$18,803	$25,399

Special_Charges_Additional_Inf

Special Charges - Additional Information (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011
Percentage Of termination benefit paid	80.00%	60.00%	61.00%	'
Accrued special charges	$7,846	$5,541	$6,479	$6,930
Accrued special charges noncurrent	587	2,213	2,173	'
Accrued special charges current	7,259	3,328	4,306	'
Litigation Costs	'	'	'	'
Accrued special charges	4,855	624	0	'
Employee Severance	'	'	'	'
Accrued special charges	1,004	2,028	3,668	2,664
Other Restructuring	'	'	'	'
Professional fees	'	'	4,066	'
Accrued special charges	$1,987	$2,889	$2,811	$4,266

Special_Charges_Summary_of_the

Special Charges Summary of the Components of Special Charges (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Restructuring Cost and Reserve	'	'	'
Litigation costs	$11,597	$3,632	$0
Employee severance and related costs	4,392	4,016	8,437
Other	940	2,298	4,737
Special charges	$16,929	$9,946	$13,174

Special_Charges_Changes_in_Acc

Special Charges Changes in Accrued Special Charges (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011
Restructuring Cost and Reserve	'	'	'	'
Litigation costs	$11,597	$3,632	$0	'
Employee severance and related costs	4,392	4,016	8,437	'
Other	940	2,298	4,737	'
Special charges	16,929	9,946	13,174	'
Special charges payments	14,624	10,884	13,625	'
Accrued special charges	7,846	5,541	6,479	6,930
Litigation Costs	'	'	'	'
Restructuring Cost and Reserve	'	'	'	'
Litigation costs	11,597	3,632	'	'
Special charges payments	7,366	3,008	'	'
Accrued special charges	4,855	624	0	'
Employee Severance	'	'	'	'
Restructuring Cost and Reserve	'	'	'	'
Employee severance and related costs	4,392	4,016	8,437	'
Special charges payments	5,416	5,656	7,433	'
Accrued special charges	1,004	2,028	3,668	2,664
Other Restructuring	'	'	'	'
Restructuring Cost and Reserve	'	'	'	'
Other	940	2,298	4,737	'
Special charges payments	1,842	2,220	6,192	'
Accrued special charges	$1,987	$2,889	$2,811	$4,266

Other_Income_Expense_Net_Detai

Other Income (Expense), Net (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Component of Other Expense, Nonoperating	'	'	'
Interest income	$2,360	$1,944	$2,195
Foreign currency exchange gain (loss)	-1,872	-2,394	-718
Gain on converstion of equity method investment to controlling interest	0	0	-1,519
Other, net	-1,008	-982	-1,420
Other income (expense), net	$520	$1,432	($1,576)

Related_Party_Transactions_Rev

Related Party Transactions Revenue Recognized From Related Party (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Related Party Transaction	'	'	'
Revenue from customers	$85,037	$56,878	$35,944
Percentage of total revenue	7.40%	5.20%	3.50%

Related_Party_Transactions_Rel

Related Party Transactions Related Party Transactions - Additional Information (Details) (USD $)	Jan. 31, 2014
In Thousands, unless otherwise specified
Related Party Transaction	'
Accounts receivable due from related party	$95,789

Supplemental_Cash_Flow_Informa2

Supplemental Cash Flow Information - Additional Information (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Schedule of Cash Flow, Supplemental	'	'	'
Interest	$12,225	$11,981	$14,686
Income taxes	11,871	10,777	8,707
Frontline	'	'	'
Schedule of Cash Flow, Supplemental	'	'	'
Returns received on investment	$5,500	$6,250	$7,015

Segment_Reporting_Additional_I

Segment Reporting - Additional Information (Detail)	12 Months Ended
	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Concentration Risk	'	'	'
Customers accounting for ten percent or more of net revenue	0	0	0
Customer Concentration Risk | Sales Revenue, Goods and Services, Net	'	'	'
Concentration Risk	'	'	'
Customer percent of total revenues	10.00%	10.00%	10.00%

Segment_Reporting_Revenues_Rel

Segment Reporting Revenues Related to Operations in Geographic Regions (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014	Oct. 31, 2013	Jul. 31, 2013	Apr. 30, 2013	Jan. 31, 2013	Oct. 31, 2012	Jul. 31, 2012	Apr. 30, 2012	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Revenues:	'	'	'	'	'	'	'	'	'	'	'
Total revenues	$401,000	$275,642	$253,216	$226,515	$331,238	$268,760	$240,811	$247,918	$1,156,373	$1,088,727	$1,014,638
United States	'	'	'	'	'	'	'	'	'	'	'
Revenues:	'	'	'	'	'	'	'	'	'	'	'
Total revenues	'	'	'	'	'	'	'	'	497,954	467,595	397,801
Other North America	'	'	'	'	'	'	'	'	'	'	'
Revenues:	'	'	'	'	'	'	'	'	'	'	'
Total revenues	'	'	'	'	'	'	'	'	15,250	13,544	18,361
North America	'	'	'	'	'	'	'	'	'	'	'
Revenues:	'	'	'	'	'	'	'	'	'	'	'
Total revenues	'	'	'	'	'	'	'	'	513,204	481,139	416,162
Europe	'	'	'	'	'	'	'	'	'	'	'
Revenues:	'	'	'	'	'	'	'	'	'	'	'
Total revenues	'	'	'	'	'	'	'	'	241,417	261,371	247,079
Japan	'	'	'	'	'	'	'	'	'	'	'
Revenues:	'	'	'	'	'	'	'	'	'	'	'
Total revenues	'	'	'	'	'	'	'	'	113,796	127,789	116,469
Asia	'	'	'	'	'	'	'	'	'	'	'
Revenues:	'	'	'	'	'	'	'	'	'	'	'
Total revenues	'	'	'	'	'	'	'	'	$287,956	$218,428	$234,928

Segment_Reporting_Total_Proper

Segment Reporting Total Property, Plant, and Equipment, Net (Details) (USD $)	Jan. 31, 2014	Jan. 31, 2013
In Thousands, unless otherwise specified
Property, plant, and equipment, net:	'	'
Property, plant, and equipment, net	$160,165	$162,402
United States	'	'
Property, plant, and equipment, net:	'	'
Property, plant, and equipment, net	116,954	121,179
Other North America	'	'
Property, plant, and equipment, net:	'	'
Property, plant, and equipment, net	141	269
North America	'	'
Property, plant, and equipment, net:	'	'
Property, plant, and equipment, net	117,095	121,448
Europe	'	'
Property, plant, and equipment, net:	'	'
Property, plant, and equipment, net	34,800	33,029
Japan	'	'
Property, plant, and equipment, net:	'	'
Property, plant, and equipment, net	637	979
Asia	'	'
Property, plant, and equipment, net:	'	'
Property, plant, and equipment, net	$7,633	$6,946

Segment_Reporting_Segment_Repo

Segment Reporting Segment Reporting Operating Segment (Details)	12 Months Ended
	Jan. 31, 2014
Segment Reporting [Abstract]	'
Number of operating segments	1

Quarterly_Financial_Informatio2

Quarterly Financial Information - Unaudited (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jan. 31, 2014	Oct. 31, 2013	Jul. 31, 2013	Apr. 30, 2013	Jan. 31, 2013	Oct. 31, 2012	Jul. 31, 2012	Apr. 30, 2012	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Quarterly Financial Information Disclosure [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Total revenues	$401,000	$275,642	$253,216	$226,515	$331,238	$268,760	$240,811	$247,918	$1,156,373	$1,088,727	$1,014,638
Gross profit	345,003	229,570	208,359	186,334	283,770	218,497	194,235	202,535	969,266	899,037	841,180
Operating Income	117,197	33,372	26,578	5,893	71,095	37,809	19,907	32,822	183,040	161,633	112,192
Net income attributable to Mentor Graphics shareholders	105,536	25,535	23,982	205	61,746	30,641	18,167	28,182	155,258	138,736	83,872
Basic (in dollars per share)	$0.91	$0.21	$0.19	$0.01	$0.50	$0.27	$0.17	$0.26	$1.33	$1.20	$0.76
Diluted (in dollars per share)	$0.89	$0.20	$0.19	$0.01	$0.49	$0.27	$0.16	$0.25	$1.29	$1.17	$0.74
Non-controlling interest adjustment to redemption value	($573)	($2,032)	($2,349)	$468	($5,272)	$0	$0	$0	($4,486)	($5,272)	$0