v3.26.1
Business segment information - Schedule of Business segment information (Detail) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Net sales:    
Total net sales $ 40,569 $ 40,272
Total Cost of sales 27,317 28,109
Total Gross margin 13,252 12,163
Total Segment selling, general and administrative expense 6,202 6,294
Operating income    
Total operating income 7,050 5,869
Interest income 677 873
Income before income taxes 7,727 6,742
Depreciation and amortization $ 868 945
Number Of Reportable Segments Not Disclosed true  
Operating Segments    
Net sales:    
Total net sales $ 40,569 40,272
Total Cost of sales 27,317 28,109
Total Gross margin 13,252 12,163
Total Segment selling, general and administrative expense 4,366 4,401
Operating income    
Total operating income 8,886 7,762
Operating Segments | Security Products    
Net sales:    
Total net sales 29,896 30,230
Total Cost of sales 19,872 21,232
Total Gross margin 10,024 8,998
Total Segment selling, general and administrative expense 3,449 3,477
Operating income    
Total operating income 6,575 5,521
Depreciation and amortization 576 644
Operating Segments | Marine Components    
Net sales:    
Total net sales 10,673 10,042
Total Cost of sales 7,445 6,877
Total Gross margin 3,228 3,165
Total Segment selling, general and administrative expense 917 924
Operating income    
Total operating income 2,311 2,241
Depreciation and amortization 292 301
Corporate    
Operating income    
Total operating income $ (1,836) $ (1,893)