Recent Accounting Pronouncements - Additional Information (Details) - USD ($) $ in Thousands	Jul. 31, 2019	Feb. 01, 2019	Jan. 31, 2019	Jul. 31, 2018
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Lease, right-of-use assets	$ 91,119		$ 0	$ 0
Lease liabilities	$ 97,581
ASU 2016-02
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Lease, right-of-use assets		$ 97,000
Lease, right-of-use assets after deferred rent liabilities and tenant allowances		91,100
Deferred rent liabilities and tenant allowances		5,900
Lease liabilities		$ 97,000