Significant Accounting Policies - Opening Balance Adjustments (Details) - USD ($) $ in Thousands	Jan. 31, 2020	Nov. 01, 2019	Oct. 31, 2019	Jan. 31, 2019
ASSETS
Operating right-of-use assets	$ 50,148	$ 53,334
Total assets	3,830,887	3,946,680	$ 3,893,346
LIABILITIES AND STOCKHOLDERS’ EQUITY
Accrued liabilities and other short-term obligations	273,305	381,256	382,740
Operating lease liabilities	18,623	20,498
Other long-term obligations	125,607	127,503	148,747
Long-term operating lease liabilities	53,333	55,564
Total liabilities and stockholders’ equity	3,830,887	3,946,680	$ 3,893,346
Short-term restructuring reserve liability	2,232			$ 1,376
Long-term restructuring reserve liability	$ 0			$ 1,187
Accounting Standards Update 2016-02
ASSETS
Operating right-of-use assets		53,334
Total assets		53,334
LIABILITIES AND STOCKHOLDERS’ EQUITY
Accrued liabilities and other short-term obligations		(1,484)
Operating lease liabilities		20,498
Other long-term obligations		(21,244)
Long-term operating lease liabilities		55,564
Total liabilities and stockholders’ equity		53,334
Operating right-of-use assets before adjustments		76,000
Deferred rent		(5,400)
Tenant improvement allowances		(6,200)
Short-term restructuring reserve liability		(1,500)
Long-term restructuring reserve liability		$ (9,600)