Basis of Presentation and Summary of Significant Accounting Policies - Restricted Cash (Details) - USD ($) $ in Thousands	Oct. 31, 2018	Jan. 31, 2018		Oct. 31, 2017
Accounting Policies [Abstract]
Restricted cash	$ 15,822	$ 14,763	[1]	$ 14,763	[2]

[1] *Prior period information has been adjusted to reflect the adoption impact of Accounting Standards Codification 606, Revenue from Contracts with Customers (ASC 606), which we adopted on February 1, 2018.

[2] * Prior period information has been adjusted to reflect the adoption impact of ASC 606 and Accounting Standards Update No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash (ASU 2016-18), which we adopted on February 1, 2018