Derivative Financial Instruments - Outstanding Currency, Forward Exchange Contracts (Detail) - Foreign Currency Forward Contracts [Member] - USD ($) $ in Thousands	Jan. 31, 2020	Jan. 31, 2019
Sell [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	$ 292,257	$ 395,395
Buy [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	476,416	525,360
Euro [Member] | Sell [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	227,292	335,775
Euro [Member] | Buy [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	118,275	204,537
British Pound [Member] | Sell [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	18,934	24,348
British Pound [Member] | Buy [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	54,818	66,809
Japanese Yen [Member] | Sell [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	37,429	28,009
Japanese Yen [Member] | Buy [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	58,672	47,997
Australian Dollar [Member] | Sell [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	345	786
Australian Dollar [Member] | Buy [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	7,817	8,012
Hong Kong Dollar [Member] | Sell [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	643
Hong Kong Dollar [Member] | Buy [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	152,452	121,578
Singapore Dollar [Member] | Sell [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	1,109	858
Singapore Dollar [Member] | Buy [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	15,987	15,115
Others [Member] | Sell [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	6,505	5,619
Others [Member] | Buy [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	$ 68,395	$ 61,312