FAIR VALUE MEASUREMENTS (Details 2) (Liability for contingent consideration, USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jul. 31, 2012	Jul. 31, 2011
Changes in the estimated fair value of liability for contingent consideration measured using significant unobservable inputs (Level 3)
Fair value measurement at the beginning of the period	$ 38,646	$ 3,686
Contingent consideration liabilities recorded for business combinations	0	904
Changes in fair values, recorded in operating expenses	(7,540)	1,881
Payments of contingent consideration	(5,902)	(4,107)
Fair value measurement at the end of the period	$ 25,204	$ 2,364
Minimum
Changes in the estimated fair value of liability for contingent consideration measured using significant unobservable inputs (Level 3)
Discount rates	3.70%
Maximum
Changes in the estimated fair value of liability for contingent consideration measured using significant unobservable inputs (Level 3)
Discount rates	17.50%