Quarterly Results of Operations - Quarterly Financial Information (Detail) - USD ($) $ / shares in Units, $ in Thousands |
3 Months Ended | 12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2015 |
Sep. 30, 2015 |
Jun. 30, 2015 |
Mar. 31, 2015 |
Dec. 31, 2014 |
Sep. 30, 2014 |
Jun. 30, 2014 |
Mar. 31, 2014 |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Quarterly results of operations | |||||||||||
| Net sales | $ 25,700 | $ 26,500 | $ 28,900 | $ 27,900 | $ 24,700 | $ 26,500 | $ 26,800 | $ 25,800 | $ 108,994 | $ 103,846 | $ 92,045 |
| Gross margin | 7,600 | 8,100 | 9,100 | 8,600 | 7,700 | 8,200 | 8,600 | 7,700 | 33,401 | 32,248 | 27,574 |
| Net income (loss) | (5,400) | 1,200 | (28,800) | 10,300 | 5,600 | 14,100 | 5,800 | 4,100 | |||
| Net income (loss) attributable to NL stockholders | $ (5,600) | $ 900 | $ (29,200) | $ 10,000 | $ 5,400 | $ 13,900 | $ 5,500 | $ 3,700 | $ (23,909) | $ 28,499 | $ (55,333) |
| Income (loss) per common share attributable to NL stockholders | $ (0.11) | $ 0.02 | $ (0.60) | $ 0.21 | $ 0.11 | $ 0.29 | $ 0.11 | $ 0.08 | |||