Deferred Costs (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jul. 31, 2022	Jul. 31, 2021	Jul. 31, 2022	Jul. 31, 2021	Jan. 31, 2022
Deferred Costs [Abstract]
Deferred costs	$ 27,877,000		$ 27,877,000		$ 33,106,000
Amortization of deferred costs	6,000,000	$ 6,000,000	12,000,000	$ 13,000,000
Impairment losses recorded in relation to the costs capitalized	$ 0	$ 0	$ 0	$ 0