CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Net income (loss)	$ 4,124	$ (998)	$ 11,498	$ 21,288
Other comprehensive income (loss), net of tax:
Currency translation	2,426	(4,500)	(3,328)	(2,805)
Total other comprehensive income (loss), net	3,431	(3,747)	(400)	(542)
Comprehensive income (loss)	7,555	(4,745)	11,098	20,746
Comprehensive income attributable to noncontrolling interest	252	540	1,127	1,744
Comprehensive income (loss) attributable to NL stockholders	7,303	(5,285)	9,971	19,002
Defined Benefit Pension Plans
Other comprehensive income (loss), net of tax:
Defined benefit plans	1,075	818	3,149	2,463
Other Postretirement Benefit Plans
Other comprehensive income (loss), net of tax:
Defined benefit plans	$ (70)	$ (65)	$ (221)	$ (200)