Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended
	Apr. 30, 2016	Apr. 30, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 38,759	$ 4,092
Other comprehensive income (loss), before tax and net of reclassification adjustments:
Foreign currency translation and other gains (losses)	10,256	(1,855)
Unrealized gains (losses) on investments	11,084	(2,389)
Other comprehensive income (loss), before tax	21,340	(4,244)
Tax effect	0	0
Other comprehensive income (loss), net of tax	21,340	(4,244)
Comprehensive income (loss)	$ 60,099	$ (152)