Condensed Consolidated Statements of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Oct. 31, 2013	Oct. 31, 2012	Oct. 31, 2013	Oct. 31, 2012
Revenues:
System and software	$ 170,835	$ 166,301	$ 444,322	$ 455,614
Service and support	104,807	102,459	311,051	301,875
Total revenues	275,642	268,760	755,373	757,489
Cost of revenues:
System and software	15,947	19,214	40,082	49,296
Service and support	29,396	29,290	88,380	86,834
Amortization of purchased technology	729	1,759	2,648	6,092
Total cost of revenues	46,072	50,263	131,110	142,222
Gross profit	229,570	218,497	624,263	615,267
Operating expenses:
Research and development	86,799	76,214	246,823	220,211
Marketing and selling	85,746	84,673	244,664	243,493
General and administration	18,917	16,965	52,452	51,702
Equity in earnings of Frontline	(1,392)	(381)	(2,739)	(1,630)
Amortization of intangible assets	1,440	1,242	4,650	4,547
Special charges	4,688	1,975	12,570	6,406
Total operating expenses	196,198	180,688	558,420	524,729
Operating income	33,372	37,809	65,843	90,538
Other income (expense), net	352	57	(879)	(239)
Interest expense	(4,967)	(4,652)	(14,649)	(13,983)
Income before income tax	28,757	33,214	50,315	76,316
Income tax expense (benefit)	3,634	1,148	1,864	(835)
Net income	25,123	32,066	48,451	77,151
Net income (loss) attributable to noncontrolling interest	(412)	1,425	(1,271)	161
Net income attributable to Mentor Graphics shareholders	$ 25,535	$ 30,641	$ 49,722	$ 76,990
Net income per share:
Basic	$ 0.21	$ 0.27	$ 0.40	$ 0.70
Diluted	$ 0.20	$ 0.27	$ 0.39	$ 0.68
Weighted average number of shares outstanding:
Basic	113,986	111,575	113,232	110,454
Diluted	117,078	114,721	116,395	113,584
Cash dividends declared per common share	$ 0.045	$ 0.000	$ 0.135	$ 0.000