Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2017
Income Tax Examination [Line Items]
Income tax examination, penalties and interest expense	$ (6,200,000)	$ 2,000,000	$ 0
Accrued income tax penalties and interest	4,200,000	$ 10,300,000
Unrecognized tax benefits, period increase (decrease)	6,000,000
Foreign Tax Authority
Income Tax Examination [Line Items]
Operating loss carryforwards	$ 23,300,000