Quarterly Results of Operations (Tables)

12 Months Ended

Dec. 31, 2016

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, 2015
Net sales	$	27.9		$	28.9		$	26.5	$	25.7
Gross margin		8.6			9.1			8.1		7.6
Net income (loss)		10.3			(28.8	)		1.2		(5.4	)
Net income (loss) attributable to NL stockholders		10.0			(29.2	)		0.9		(5.6	)
Income (loss) per common share attributable to    NL stockholders	$	.21		$	(.60	)	$	.02	$	(.11	)
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
Net income (loss) attributable to NL stockholders		(2.5	)		0.8			7.4		9.6
Income (loss) per common share attributable to    NL stockholders	$	(.05	)	$	.02		$	.15	$	.20