Income Taxes - Schedule of Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2017
Income Tax Disclosure [Abstract]
Beginning balance	$ 34,117	$ 37,977	$ 30,211
Additions based on tax positions related to the current year	3,922	7,892	7,830
Additions for tax positions of prior years	109	28	911
Reductions for tax positions in prior years	(552)	(11,313)	0
Settlements for prior periods	0	0	0
Lapse of applicable statute of limitations	(65)	(467)	(975)
Ending balance	$ 37,531	$ 34,117	$ 37,977