CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Net income (loss)	$ (998)	$ (14,872)	$ 21,288	$ (42,098)
Other comprehensive income (loss), net of tax:
Currency translation	(4,500)	1,103	(2,805)	(2,414)
Total other comprehensive income (loss), net	(3,747)	1,997	(542)	299
Comprehensive income (loss)	(4,745)	(12,875)	20,746	(41,799)
Comprehensive income attributable to noncontrolling interest	540	514	1,744	1,654
Comprehensive income (loss) attributable to NL stockholders	(5,285)	(13,389)	19,002	(43,453)
Defined Benefit Pension Plans
Other comprehensive income (loss), net of tax:
Defined benefit plans	818	959	2,463	2,916
Other Postretirement Benefit Plans
Other comprehensive income (loss), net of tax:
Defined benefit plans	$ (65)	$ (65)	$ (200)	$ (203)