Quarterly Results of Operations (Tables)

12 Months Ended

Dec. 31, 2017

Quarterly Financial Information Disclosure [Abstract]

Quarterly Results of Operations

	Quarter ended
	March 31			June 30		Sept. 30		Dec. 31
	(In millions, except per share data)
Year ended December 31, 2016
Net sales	$	27.1		$	27.1	$	28.4	$	26.3
Gross margin		8.2			8.5		9.4		9.1
Net income (loss)		(2.2	)		1.2		7.8		10.0
Amounts attributable to NL stockholders:
Net income (loss)		(2.5	)		0.8		7.4		9.6
Income (loss) per common share	$	(.05	)	$	.02	$	.15	$	.20
Year ended December 31, 2017
Net sales	$	29.9		$	30.0	$	27.0	$	25.1
Gross margin		9.7			9.5		8.2		7.4
Net income		8.8			41.6		17.8		49.6
Amounts attributable to NL stockholders:
Net income		8.3			41.2		17.5		49.1
Income per common share	$	.17		$	.85	$	.36	$	1.00