Consolidated Statements of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2013
Revenues:
System and software	$ 799,151us-gaap_LicensesRevenue	$ 737,790us-gaap_LicensesRevenue	$ 681,881us-gaap_LicensesRevenue
Service and support	444,982us-gaap_MaintenanceRevenue	418,583us-gaap_MaintenanceRevenue	406,846us-gaap_MaintenanceRevenue
Total revenues	1,244,133us-gaap_Revenues	1,156,373us-gaap_Revenues	1,088,727us-gaap_Revenues
Cost of revenues:
System and software	69,811us-gaap_LicenseCosts	65,288us-gaap_LicenseCosts	64,280us-gaap_LicenseCosts
Service and support	127,403us-gaap_CostOfServicesMaintenanceCosts	118,221us-gaap_CostOfServicesMaintenanceCosts	117,609us-gaap_CostOfServicesMaintenanceCosts
Amortization of purchased technology	7,099us-gaap_CostOfGoodsSoldAmortization	3,598us-gaap_CostOfGoodsSoldAmortization	7,801us-gaap_CostOfGoodsSoldAmortization
Total cost of revenues	204,313us-gaap_CostOfRevenue	187,107us-gaap_CostOfRevenue	189,690us-gaap_CostOfRevenue
Gross profit	1,039,820us-gaap_GrossProfit	969,266us-gaap_GrossProfit	899,037us-gaap_GrossProfit
Operating expenses:
Research and development	381,125	348,817	313,962
Marketing and selling	365,688us-gaap_SellingAndMarketingExpense	342,799us-gaap_SellingAndMarketingExpense	338,653us-gaap_SellingAndMarketingExpense
General and administration	79,193us-gaap_GeneralAndAdministrativeExpense	75,543us-gaap_GeneralAndAdministrativeExpense	70,692us-gaap_GeneralAndAdministrativeExpense
Equity in earnings of Frontline	(5,653)	(4,092)	(1,764)
Amortization of intangible assets	8,166us-gaap_AmortizationOfIntangibleAssets	6,230us-gaap_AmortizationOfIntangibleAssets	5,915us-gaap_AmortizationOfIntangibleAssets
Special charges	23,490ment_SpecialCharges	16,929ment_SpecialCharges	9,946ment_SpecialCharges
Total operating expenses	852,009us-gaap_OperatingExpenses	786,226us-gaap_OperatingExpenses	737,404us-gaap_OperatingExpenses
Operating income	187,811us-gaap_OperatingIncomeLoss	183,040us-gaap_OperatingIncomeLoss	161,633us-gaap_OperatingIncomeLoss
Other expense, net	(777)us-gaap_OtherNonoperatingIncomeExpense	(520)us-gaap_OtherNonoperatingIncomeExpense	(1,432)us-gaap_OtherNonoperatingIncomeExpense
Interest expense	(19,276)us-gaap_InterestExpense	(19,452)us-gaap_InterestExpense	(18,866)us-gaap_InterestExpense
Income before income tax	167,758	163,068	141,335
Income tax expense	22,581us-gaap_IncomeTaxExpenseBenefit	9,510us-gaap_IncomeTaxExpenseBenefit	2,701us-gaap_IncomeTaxExpenseBenefit
Net income	145,177us-gaap_ProfitLoss	153,558us-gaap_ProfitLoss	138,634us-gaap_ProfitLoss
Less: Loss attributable to noncontrolling interest	(1,962)	(1,700)	(102)
Net income attributable to Mentor Graphics shareholders	$ 147,139us-gaap_NetIncomeLoss	$ 155,258us-gaap_NetIncomeLoss	$ 138,736us-gaap_NetIncomeLoss
Net income per share:
Basic (in dollars per share)	$ 1.28us-gaap_EarningsPerShareBasic	$ 1.33us-gaap_EarningsPerShareBasic	$ 1.20us-gaap_EarningsPerShareBasic
Diluted (in dollars per share)	$ 1.26us-gaap_EarningsPerShareDiluted	$ 1.29us-gaap_EarningsPerShareDiluted	$ 1.17us-gaap_EarningsPerShareDiluted
Weighted average number of shares outstanding:
Basic (in shares)	114,635	113,671	110,998
Diluted (in shares)	117,078	116,702	114,017
Cash dividends declared per common share	$ 0.20	$ 0.18	$ 0

Amount of expenses associated with special charges including employee terminations, expenses related to certain litigation, expenses incurred related to acquisitions, excess facility costs, and other asset related charges. Excludes expenses related to a discontinued operation or an asset retirement obligation.

No definition available.