Leases - Lease cash flow information (Details) $ in Thousands	9 Months Ended
	Oct. 31, 2019 USD ($)
Leases [Abstract]
Cash paid for amounts included in the measurement of lease liabilities	$ 24,403
Operating lease right-of-use assets obtained in exchange for operating lease liabilities	$ 14,937
Weighted-average remaining lease term (years)	5 years 8 months 15 days
Weighted-average discount rate (as a percent)	6.52%