CONDENSED CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 73,202	$ 72,560
Restricted cash and cash equivalents	3,420	3,995
Accounts and other receivables, net	12,441	9,256
Inventories, net	16,824	16,863
Prepaid expenses and other	824	792
Deferred income taxes	4,567	4,567
Total current assets	111,278	108,033
Other assets:
Marketable securities	89,544	92,131
Investment in Kronos Worldwide, Inc.	218,695	237,719
Goodwill	27,156	27,156
Other assets, net	2,145	2,143
Deferred income taxes	20	20
Total other assets	337,560	359,169
Property and equipment:
Land	5,138	5,138
Buildings	21,176	21,176
Equipment	62,832	62,264
Construction in progress	1,140	909
Property and equipment, gross	90,286	89,487
Less accumulated depreciation	56,811	55,931
Net property and equipment	33,475	33,556
Total assets	482,313	500,758
Current liabilities:
Accounts payable	5,270	6,115
Accrued and other current liabilities	7,825	11,521
Accrued environmental remediation and related costs	7,044	6,984
Income taxes	14	7
Total current liabilities	20,153	24,627
Noncurrent liabilities:
Accrued pension cost	11,760	12,242
Accrued postretirement benefits (OPEB) costs	3,210	3,341
Accrued environmental remediation and related costs	102,791	103,031
Deferred income taxes	83,145	87,725
Other	13,676	18,342
Total noncurrent liabilities	214,582	224,681
NL stockholders' equity:
Common stock	6,085	6,085
Additional paid-in capital	300,388	300,388
Retained earnings	122,630	112,588
Accumulated other comprehensive loss	(196,186)	(182,039)
Total NL stockholders' equity	232,917	237,022
Noncontrolling interest in subsidiary	14,661	14,428
Total equity	247,578	251,450
Total liabilities and equity	482,313	500,758
Commitments and contingencies (Notes 12 and 13)