Equity (Details) $ / shares in Units, $ in Thousands	6 Months Ended
	Jul. 31, 2017 USD ($) vote $ / shares shares	Apr. 30, 2017 $ / shares shares	Jan. 31, 2017 USD ($) $ / shares shares
Class of Stock [Line Items]
Preferred stock shares authorized (in shares)	50,000,000	50,000,000	0
Preferred stock par value (in dollars per share) | $ / shares	$ 0.001	$ 0.001	$ 0.001
Preferred stock shares issued (in shares)	0		0
Preferred stock shares outstanding (in shares)	0		0
Common stock shares authorized (in shares)	500,000,000		200,000,000
Common stock par value (in dollars per share) | $ / shares	$ 0.001		$ 0.001
Common stock number of votes per share | vote	1
Treasury stock (in shares)	6,505,334
Treasury stock | $	$ 11,905		$ 11,905
Common Stock
Class of Stock [Line Items]
Conversion of preferred stock (in shares)	43,594,000