CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS)
Net income (loss)	$ (35,371)	$ 69,261	$ 582
Other comprehensive income (loss), net of tax:
Currency translation	7,911	(8,304)	1,072
Defined benefit pension plans	19,307	4,707	2,484
Marketable debt securities		15	53
Other postretirement benefit plans	71	(153)	(221)
Total other comprehensive income (loss), net	27,289	(3,735)	3,388
Comprehensive income (loss)	(8,082)	65,526	3,970
Comprehensive income attributable to noncontrolling interest	2,455	2,033	2,908
Comprehensive income (loss) attributable to NL stockholders	$ (10,537)	$ 63,493	$ 1,062