STOCKHOLDERS' EQUITY STOCKHOLDERS' EQUITY - SCHEDULE OF ACCUMULATED OTHER COMPREHENSIVE LOSS (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2013	Jul. 31, 2012
Activity in Accumulated Other Comprehensive Loss
Accumulated other comprehensive loss - beginning balance			$ (44,225)
Other comprehensive income (loss) before reclassifications			(7,327)
Amounts reclassified out of accumulated other comprehensive loss	(1,521)	532	(2,231)	690
Net other comprehensive income (loss), current period			(9,558)
Accumulated other comprehensive loss - ending balance	(53,783)		(53,783)
Unrealized gains on derivative instruments designated as hedges
Activity in Accumulated Other Comprehensive Loss
Accumulated other comprehensive loss - beginning balance			2,447
Other comprehensive income (loss) before reclassifications			3,319
Amounts reclassified out of accumulated other comprehensive loss			(2,231)
Net other comprehensive income (loss), current period			1,088
Accumulated other comprehensive loss - ending balance	3,535		3,535
Unrealized losses on available-for-sale investments
Activity in Accumulated Other Comprehensive Loss
Accumulated other comprehensive loss - beginning balance			0
Other comprehensive income (loss) before reclassifications			(122)
Amounts reclassified out of accumulated other comprehensive loss			0
Net other comprehensive income (loss), current period			(122)
Accumulated other comprehensive loss - ending balance	(122)		(122)
Foreign currency translation adjustments
Activity in Accumulated Other Comprehensive Loss
Accumulated other comprehensive loss - beginning balance			(46,672)
Other comprehensive income (loss) before reclassifications			(10,524)
Amounts reclassified out of accumulated other comprehensive loss			0
Net other comprehensive income (loss), current period			(10,524)
Accumulated other comprehensive loss - ending balance	$ (57,196)		$ (57,196)