Quarterly Results of Operations - Quarterly Financial Information (Detail) - USD ($) $ / shares in Units, $ in Thousands |
3 Months Ended | 12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2016 |
Sep. 30, 2016 |
Jun. 30, 2016 |
Mar. 31, 2016 |
Dec. 31, 2015 |
Sep. 30, 2015 |
Jun. 30, 2015 |
Mar. 31, 2015 |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Quarterly results of operations | |||||||||||
| Net sales | $ 26,300 | $ 28,400 | $ 27,100 | $ 27,100 | $ 25,700 | $ 26,500 | $ 28,900 | $ 27,900 | $ 108,920 | $ 108,994 | $ 103,846 |
| Gross margin | 9,100 | 9,400 | 8,500 | 8,200 | 7,600 | 8,100 | 9,100 | 8,600 | 35,167 | 33,401 | 32,248 |
| Net income (loss) | 10,000 | 7,800 | 1,200 | (2,200) | (5,400) | 1,200 | (28,800) | 10,300 | |||
| Net income (loss) attributable to NL stockholders | $ 9,600 | $ 7,400 | $ 800 | $ (2,500) | $ (5,600) | $ 900 | $ (29,200) | $ 10,000 | $ 15,325 | $ (23,909) | $ 28,499 |
| Income (loss) per common share attributable to NL stockholders | $ 0.20 | $ 0.15 | $ 0.02 | $ (0.05) | $ (0.11) | $ 0.02 | $ (0.60) | $ 0.21 | $ 0.31 | $ (0.49) | $ 0.59 |