Deferred Costs (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Oct. 31, 2022	Oct. 31, 2021	Oct. 31, 2022	Oct. 31, 2021	Jan. 31, 2022
Deferred Costs [Abstract]
Deferred costs	$ 27,875,000		$ 27,875,000		$ 33,106,000
Amortization of deferred costs	5,000,000	$ 7,000,000	17,000,000	$ 19,000,000
Impairment losses recorded in relation to the costs capitalized	$ 0	$ 0	$ 0	$ 0