Condensed Consolidated Statements of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2013	Jul. 31, 2012
Revenues:
System and software	$ 150,203	$ 139,957	$ 273,487	$ 289,313
Service and support	103,013	100,854	206,244	199,416
Total revenues	253,216	240,811	479,731	488,729
Cost of revenues:
System and software	15,236	15,292	24,135	30,082
Service and support	28,909	29,130	58,984	57,544
Amortization of purchased technology	712	2,154	1,919	4,333
Total cost of revenues	44,857	46,576	85,038	91,959
Gross profit	208,359	194,235	394,693	396,770
Operating expenses:
Research and development	80,307	72,951	160,024	143,997
Marketing and selling	79,811	79,068	158,918	158,820
General and administration	17,198	18,629	33,535	34,737
Equity in earnings of Frontline	(950)	(662)	(1,347)	(1,249)
Amortization of intangible assets	1,556	1,599	3,210	3,305
Special charges	3,859	2,743	7,882	4,431
Total operating expenses	181,781	174,328	362,222	344,041
Operating income	26,578	19,907	32,471	52,729
Other expense, net	(272)	(379)	(1,231)	(296)
Interest expense	(4,897)	(4,737)	(9,682)	(9,331)
Income before income tax	21,409	14,791	21,558	43,102
Income tax benefit	(2,338)	(2,764)	(1,770)	(1,983)
Net income	23,747	17,555	23,328	45,085
Net loss attributable to noncontrolling interest	(235)	(612)	(859)	(1,264)
Net income attributable to Mentor Graphics shareholders	$ 23,982	$ 18,167	$ 24,187	$ 46,349
Net income per share:
Basic (in dollars per share)	$ 0.19	$ 0.17	$ 0.20	$ 0.42
Diluted (in dollars per share)	$ 0.19	$ 0.16	$ 0.19	$ 0.41
Weighted average number of shares outstanding:
Basic (in shares)	112,988	109,875	112,851	109,891
Diluted (in shares)	116,295	113,046	116,014	113,078
Cash dividends declared per common share	$ 0.045	$ 0.000	$ 0.090	$ 0.000