Commitments and Contingencies - Additional Information (Details) - USD ($)	Apr. 30, 2018	Mar. 31, 2018	Jan. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Base rent obligation	$ 154,900,000		$ 113,000,000
Lessee, Lease, Description [Line Items]
Outstanding letters of credit	$ 11,500,000		$ 9,600,000
Letter of Credit
Lessee, Lease, Description [Line Items]
Principal amount		$ 1,500,000.0