PROPERTY AND EQUIPMENT - Property and Equipment at Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 227,999	$ 210,343
Less: accumulated depreciation	(151,976)	(123,936)
Property and equipment, net	$ 76,023	86,407
Machinery and equipment
Property, Plant and Equipment [Line Items]
Estimated useful lives of fixed assets	5 years
Property and equipment, gross	$ 1,867	2,270
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 75,808	78,403
Leasehold improvements | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful lives of fixed assets	3 years
Leasehold improvements | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful lives of fixed assets	13 years
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 109,284	97,133
Furniture and fixtures | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful lives of fixed assets	3 years
Furniture and fixtures | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful lives of fixed assets	10 years
Computer equipment and software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 41,040	$ 32,537
Computer equipment and software | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful lives of fixed assets	2 years
Computer equipment and software | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful lives of fixed assets	5 years