Income Taxes Difference of Effective Tax Rate from Federal Tax Rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2014
Disclosure Difference of Effective Tax Rate From Federal Tax Rate [Abstract]
Federal tax, at statutory rate	$ 41,626	$ 58,725	$ 57,074
State tax, net of federal benefit	(60)	900	355
Impact of international operations including withholding taxes and other reserves	7,143	(27,042)	(46,632)
Repatriation of foreign subsidiary earnings	354	21,969	20,367
Foreign tax credits	(2,382)	(5,143)	(5,489)
Tax credits (excluding foreign tax credits)	(11,539)	(8,089)	(12,571)
Amortization of deferred charge	(167)	1,168	(2,311)
Change in deferred tax assets valuation allowance	(21,055)	(26,443)	(5,929)
Stock-based compensation expense	3,402	2,929	2,593
Non-deductible meals and entertainment	1,177	1,238	1,087
Other, net	6,254	2,369	966
Provision (benefit) for income taxes	$ 24,753	$ 22,581	$ 9,510