Note 4 - Revenue Recognition - Revenues by Revenue Class (Details) - USD ($) $ in Thousands	12 Months Ended
Jan. 31, 2024	Jan. 31, 2023
Sales by product	$ 150,668	$ 142,569
Sales by product, percent	100.00%	100.00%
Product [Member] \| Transferred at Point in Time [Member]
Sales by product	$ 10,368	$ 14,626
Sales by product, percent	7.00%	10.00%
Specialty Piping Systems And Coating [Member] \| Transferred at Point in Time Using Input Method [Member]
Sales by product	$ 51,977	$ 44,648
Sales by product, percent	34.00%	31.00%
Specialty Piping Systems And Coating [Member] \| Transferred at Point in Time Using Output Method [Member]
Sales by product	$ 88,323	$ 83,295
Sales by product, percent	59.00%	59.00%

Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

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+ Details