Information about Geographic Areas - Revenues by Geographic Area (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jan. 31, 2020	Oct. 31, 2019	Jul. 31, 2019	Apr. 30, 2019	Jan. 31, 2019	Oct. 31, 2018	Jul. 31, 2018	Apr. 30, 2018	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Revenues by geography
Total revenues	$ 311,508	$ 280,921	$ 266,900	$ 244,752	$ 232,323	$ 224,731	$ 209,609	$ 195,547	$ 1,104,081	$ 862,210	$ 690,559
North America
Revenues by geography
Total revenues									607,704	480,713	377,797
Europe
Revenues by geography
Total revenues									310,215	228,784	181,940
Asia Pacific
Revenues by geography
Total revenues									151,052	124,431	107,397
Rest of World
Revenues by geography
Total revenues									$ 35,110	$ 28,282	$ 23,425