Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2014
Revenues:
System and software	$ 700,621	$ 799,151	$ 737,790
Service and support	480,367	444,982	418,583
Total revenues	1,180,988	1,244,133	1,156,373
Cost of revenues:
System and software	48,330	69,811	65,288
Service and support	134,025	127,403	118,221
Amortization of purchased technology	7,303	7,099	3,598
Total cost of revenues	189,658	204,313	187,107
Gross profit	991,330	1,039,820	969,266
Operating expenses:
Research and development	381,440	381,125	348,817
Marketing and selling	351,344	365,688	342,799
General and administration	73,853	79,193	75,543
Equity in earnings of Frontline	(5,849)	(5,653)	(4,092)
Amortization of intangible assets	8,716	8,166	6,230
Special charges	45,081	23,490	16,929
Total operating expenses	854,585	852,009	786,226
Operating income:	136,745	187,811	183,040
Other income (expense), net	1,612	(777)	(520)
Interest expense	(19,428)	(19,276)	(19,452)
Income before income tax	118,929	167,758	163,068
Income tax expense	24,753	22,581	9,510
Net income	94,176	145,177	153,558
Less: Loss attributable to noncontrolling interest	(2,101)	(1,962)	(1,700)
Net income attributable to Mentor Graphics shareholders	$ 96,277	$ 147,139	$ 155,258
Net income per share:
Basic	$ 0.83	$ 1.28	$ 1.33
Diluted	$ 0.81	$ 1.26	$ 1.29
Weighted average number of shares outstanding:
Basic	116,701	114,635	113,671
Diluted	119,263	117,078	116,702
Cash dividends declared per common share	$ 0.22	$ 0.20	$ 0.18