CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 99,948	$ 98,316
Restricted cash and cash equivalents	3,277	3,370
Accounts and other receivables, net	12,888	10,670
Inventories, net	16,328	15,382
Receivable from affiliate	1,899	1,767
Prepaid expenses and other	1,980	1,162
Total current assets	136,320	130,667
Other assets:
Notes receivable from affiliate	38,000	38,200
Marketable securities	87,100	88,681
Investment in Kronos Worldwide, Inc.	249,028	229,543
Goodwill	27,156	27,156
Other assets, net	5,153	4,843
Total other assets	406,437	388,423
Property and equipment:
Land	5,146	5,146
Buildings	22,780	23,044
Equipment	68,154	67,926
Construction in progress	850	569
Property and equipment, gross	96,930	96,685
Less accumulated depreciation	64,818	64,159
Net property and equipment	32,112	32,526
Total assets	574,869	551,616
Current liabilities:
Accounts payable	3,921	4,116
Accrued and other current liabilities	7,090	9,707
Accrued environmental remediation and related costs	18,252	5,302
Payable to affiliates	429	429
Income taxes	46	30
Total current liabilities	29,738	19,584
Noncurrent liabilities:
Long-term debt from affiliate	500	500
Accrued pension costs	11,970	12,194
Accrued postretirement benefits (OPEB) costs	1,777	1,846
Accrued environmental remediation and related costs	97,506	106,607
Deferred income taxes	53,661	49,315
Other	8,486	8,492
Total noncurrent liabilities	173,900	178,954
NL stockholders' equity:
Common stock	6,089	6,089
Additional paid-in capital	300,866	300,866
Retained earnings	280,421	220,104
Accumulated other comprehensive loss	(234,305)	(191,737)
Total NL stockholders' equity	353,071	335,322
Noncontrolling interest in subsidiary	18,160	17,756
Total equity	371,231	353,078
Total liabilities and equity	574,869	551,616
Commitments and contingencies (Note 14)