Acquisition (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2017	Jan. 31, 2016
Business Acquisition [Line Items]
Business acquisition, name of acquired entity	Perma-Pipe Canada, Ltd
Business acquisition, description of acquired entity	a coating and insulation company in Camrose, Alberta
Business acquisition, date of acquisition agreement	Feb. 04, 2016
Equity method investment, ownership percentage	49.00%
Cash purchase consideration	$ 7,587
Loan payable purchase consideration	2,000
Purchase consideration to third party	9,587
Fair value of 49% previously held equity interest	7,492
Total purchase consideration	17,079
Assets acquired, cash and equivalents	2,915
Assets acquired property, plant, and equipment	13,124
Goodwill	2,279	$ 0
Assets acquired net working capital	406
Assets acquired other assets (liabilities) net	(1,645)
Net assets acquired	17,079
Business acquisition, transaction costs	200
Loss on consolidation of joint venture	$ 1,620	$ 0