Revenue (Details) - USD ($) $ in Thousands	Jul. 31, 2018	Jan. 31, 2018	Jul. 31, 2017
ASSETS
Trade receivables, net	$ 83,818	$ 83,098	$ 81,513
Inventories	171,417	151,676	176,967
Deferred and non-current income taxes	8,074	6,443	24,924
Liabilities
Accrued liabilities	50,054	47,943	44,192
Income taxes payable	5,996	2,989	1,730
Deferred and non-current income taxes payable	29,718	$ 33,063	$ 7,759
ASU 2014-09 \| Balances Without Adoption
ASSETS
Trade receivables, net	82,760
Inventories	171,965
Deferred and non-current income taxes	8,099
Liabilities
Accrued liabilities	49,893
Income taxes payable	5,957
Deferred and non-current income taxes payable	29,706
ASU 2014-09 \| Impact of Adoption
ASSETS
Trade receivables, net	1,058
Inventories	(548)
Deferred and non-current income taxes	(25)
Liabilities
Accrued liabilities	161
Income taxes payable	39
Deferred and non-current income taxes payable	$ 12

Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.

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