Stockholders Equity (Tables)

3 Months Ended

Mar. 31, 2021

Stockholders Equity Note [Abstract]

Schedule of Changes in Accumulated Other Comprehensive Loss

Accumulated other comprehensive loss - Changes in accumulated other comprehensive loss attributable to NL stockholders, including amounts resulting from our investment in Kronos Worldwide (see Note 5), are presented in the table below.

	Three months ended
	March 31,
	2020			2021
	(In thousands)
Accumulated other comprehensive loss, net of tax:
Currency translation:
Balance at beginning of period	$	(172,843	)	$	(169,575	)
Other comprehensive income (loss)		(10,118	)		545
Balance at end of period	$	(182,961	)	$	(169,030	)
Defined benefit pension plans:
Balance at beginning of period	$	(78,257	)	$	(80,704	)
Other comprehensive income - amortization of net   losses included in net periodic pension cost		1,043			1,151
Balance at end of period	$	(77,214	)	$	(79,553	)
OPEB plans:
Balance at beginning of period	$	(590	)	$	(910	)
Other comprehensive loss - amortization of net   gains included in net periodic OPEB cost		(80	)		(71	)
Balance at end of period	$	(670	)	$	(981	)
Total accumulated other comprehensive loss:
Balance at beginning of period	$	(251,690	)	$	(251,189	)
Other comprehensive income (loss)		(9,155	)		1,625
Balance at end of period	$	(260,845	)	$	(249,564	)