Note 4 - Revenue Recognition - Revenues by Revenue Class (Details) - USD ($) $ in Thousands	3 Months Ended
Apr. 30, 2026	Apr. 30, 2025
Sales by product	$ 50,265	$ 46,747
Sales by product, percent	100.00%	100.00%
Product [Member] \| Transferred at Point in Time [Member]
Sales by product	$ 3,082	$ 3,640
Sales by product, percent	6.00%	8.00%
Specialty Piping Systems And Coating [Member] \| Transferred at Point in Time Using Input Method [Member]
Sales by product	$ 14,382	$ 12,060
Sales by product, percent	29.00%	26.00%
Specialty Piping Systems And Coating [Member] \| Transferred at Point in Time Using Output Method [Member]
Sales by product	$ 32,801	$ 31,047
Sales by product, percent	65.00%	66.00%

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