Deferred Costs - Additional Information (Detail) - USD ($)	3 Months Ended
	Apr. 30, 2021	Apr. 30, 2020	Jan. 31, 2021
Deferred Costs [Abstract]
Deferred costs	$ 40,007,000		$ 42,072,000
Amortization of deferred costs	6,000,000	$ 5,000,000
Impairment losses recorded in relation to the costs capitalized	$ 0	$ 0