Employee Incentive Plans - Schedule of Restricted Stock Unit Activity (Details) - RSUs	12 Months Ended
	Jan. 31, 2018 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding as of January 31, 2017 (in shares) | shares	0
Granted during period (in shares) | shares	3,012,111
Vested during period (in shares) | shares	0
Forfeited during period (in shares) | shares	(149,182)
Outstanding as of January 31, 2018 (in shares) | shares	2,862,929
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Outstanding as of January 31, 2017 (in dollars per share) | $ / shares	$ 0.00
Granted during period (in dollars per share) | $ / shares	24.37
Vested during period (in dollars per share) | $ / shares	0.00
Forfeited during period (in dollars per share) | $ / shares	24.15
Outstanding as of January 31, 2018 (in dollars per share) | $ / shares	$ 24.38