Revenue Recognition (Details) - USD ($) $ in Thousands	Oct. 31, 2018	Jan. 31, 2018		Oct. 31, 2017
Assets
Accounts receivable, net	$ 819,636	$ 294,430	[1]	$ 601,179	[1]
Inventories	616,162	553,323		592,822
Prepaid expenses and other current assets	82,933	51,014		34,841
Deferred income tax assets, net	28,336	11,439		16,169
Liabilities
Accrued expenses	137,878	95,055		128,891
Customer refund liabilities	235,400
Equity
Retained earnings	734,800	$ 674,542		$ 675,084
Without Adoption of ASC 606
Assets
Accounts receivable, net	646,333
Inventories	653,664
Prepaid expenses and other current assets	48,991
Deferred income tax assets, net	11,792
Liabilities
Accrued expenses	136,627
Equity
Retained earnings	785,164
Impact of Adoption of ASC 606
Assets
Accounts receivable, net	173,303
Inventories	(37,502)
Prepaid expenses and other current assets	33,942
Deferred income tax assets, net	16,544
Liabilities
Accrued expenses	1,251
Customer refund liabilities	235,400
Equity
Retained earnings	$ (50,364)

[1] Also, net of accrued returns and sales discounts