Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2016
Cash paid during the year for:
Interest	$ 1,223	$ 1,121	$ 797
Income taxes, net	$ 20,366	22,768	$ 22,500
Supplemental disclosures of non-cash investing activities:
Additions to property, plant and equipment included in accrued liabilities		$ 4