Stockholders' Equity - Additional Information (Details) $ / shares in Units, $ in Millions	1 Months Ended	12 Months Ended
	Apr. 30, 2018 USD ($) shares	Jan. 31, 2019 vote class $ / shares shares	Oct. 31, 2018 $ / shares	Apr. 04, 2018 $ / shares	Jan. 31, 2018 $ / shares shares	Oct. 31, 2015 shares
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)		20,000,000			20,000,000	20,000,000
Preferred stock, shares issued (in shares)		0			0
Preferred stock, shares outstanding (in shares)		0			0
Number of classes of stock | class		2
Common stock, shares authorized (in shares)		2,250,000,000			2,250,000,000
Common stock, shares issued (in shares)		220,979,000			204,364,000
Common stock, shares outstanding (in shares)		220,979,000			204,364,000
Closing price of stock (in dollars per share) | $ / shares		$ 17.91
Class A common stock
Class of Stock [Line Items]
Stock Repurchased and Retired During Period, Shares	1,008,573
Common stock, shares authorized (in shares)		2,000,000,000			2,000,000,000
Common stock, par value per share (in dollars per share) | $ / shares		$ 0.0001			$ 0.0001
Common stock, shares issued (in shares)		243,523,831			129,502,000
Common stock, shares outstanding (in shares)		243,524,000			129,502,000
Common stock, entitled votes per share (in votes per share) | vote		1
Stock Repurchased and Retired During Period, Value | $	$ 20.0
Closing price of stock (in dollars per share) | $ / shares			$ 17.91	$ 19.83
Class B common stock
Class of Stock [Line Items]
Common stock, shares authorized (in shares)		250,000,000			250,000,000
Common stock, par value per share (in dollars per share) | $ / shares		$ 0.0001			$ 0.0001
Convertible Stock, Automatic Conversion, Portion Of Outstanding Stock, Percentage		10.00%
Common stock, shares issued (in shares)		0			91,477,000
Common stock, shares outstanding (in shares)		0			91,477,000
Common stock, entitled votes per share (in votes per share) | vote		10