CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 134,826	$ 137,039
Restricted cash and cash equivalents	2,695	2,695
Accounts and other receivables, net	17,208	11,142
Receivables from affiliates		313
Inventories, net	18,153	18,337
Prepaid expenses and other	2,222	1,638
Total current assets	175,104	171,164
Other assets:
Restricted cash and cash equivalents	25,540	25,538
Note receivable from affiliate	29,200	29,500
Marketable securities	24,566	18,206
Investment in Kronos Worldwide, Inc.	243,732	242,374
Goodwill	27,156	27,156
Other assets, net	5,321	5,262
Total other assets	355,515	348,036
Property and equipment:
Land	4,940	4,940
Buildings	23,146	23,146
Equipment	68,659	68,227
Construction in progress	935	1,010
Property and equipment, gross	97,680	97,323
Less accumulated depreciation	69,219	68,373
Net property and equipment	28,461	28,950
Total assets	559,080	548,150
Current liabilities:
Accounts payable	3,060	2,647
Accrued litigation settlement	11,887	11,830
Accrued and other current liabilities	7,036	10,253
Accrued environmental remediation and related costs	2,167	2,027
Payables to affiliates	696	725
Income taxes	32	25
Total current liabilities	24,878	27,507
Noncurrent liabilities:
Long-term debt from affiliate	500	500
Accrued environmental remediation and related costs	90,848	91,389
Long-term litigation settlement	49,637	49,403
Deferred income taxes	36,763	33,830
Accrued pension costs	5,962	6,392
Other	3,673	3,780
Total noncurrent liabilities	187,383	185,294
NL stockholders' equity:
Common stock	6,098	6,098
Additional paid-in capital	300,097	299,093
Retained earnings	268,205	257,875
Accumulated other comprehensive loss	(249,564)	(251,189)
Total NL stockholders' equity	324,836	311,877
Noncontrolling interest in subsidiary	21,983	23,472
Total equity	346,819	335,349
Total liabilities and equity	559,080	548,150
Commitments and contingencies (Note 14)