Leases - Lease assets and liabilities (Details) - USD ($) $ in Thousands	Apr. 30, 2022	Jan. 31, 2022	Apr. 30, 2021
Assets and Liabilities, Lessee [Abstract]
Operating lease assets	$ 164,607	$ 169,595	$ 180,715
Classification of operating lease assets	Operating lease assets
Current operating lease liabilities	$ 41,112	42,763	43,656
Classification current operating lease liabilities	Current operating lease liabilities
Noncurrent operating lease liabilities	$ 139,686	142,868	155,218
Classification of noncurrent operating liabilities	Noncurrent operating lease liabilities
Total lease liabilities	$ 180,798	$ 185,631	$ 198,874