Leases - Lease assets and liabilities (Details) - USD ($) $ in Thousands	Oct. 31, 2021	Jan. 31, 2021	Oct. 31, 2020
Assets and Liabilities, Lessee [Abstract]
Operating lease assets	$ 176,530	$ 186,070	$ 181,187
Classification of operating lease assets	Operating lease assets
Total lease assets	$ 176,530	186,070	181,187
Current operating lease liabilities	$ 45,117	43,560	65,554
Classification current operating lease liabilities	Current operating lease liabilities
Noncurrent operating lease liabilities	$ 147,688	161,668	157,983
Classification of noncurrent operating liabilities	Noncurrent operating lease liabilities
Total lease liabilities	$ 192,805	$ 205,228	$ 223,537