CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 102,056	$ 96,462
Restricted cash and cash equivalents	3,399	3,246
Accounts and other receivables, net	12,682	8,977
Inventories, net	14,124	15,098
Prepaid expenses and other	1,586	981
Total current assets	133,847	124,764
Other assets:
Marketable securities	22,566	19,260
Investment in Kronos Worldwide, Inc.	133,000	140,695
Goodwill	27,156	27,156
Other assets, net	3,578	3,331
Deferred income taxes	11	11
Total other assets	186,311	190,453
Property and equipment:
Land	5,138	5,138
Buildings	22,788	21,502
Equipment	65,445	64,051
Construction in progress	455	1,567
Property and equipment, gross	93,826	92,258
Less accumulated depreciation	60,003	58,152
Net property and equipment	33,823	34,106
Total assets	353,981	349,323
Current liabilities:
Accounts payable	4,378	4,557
Accrued and other current liabilities	8,469	10,783
Accrued environmental remediation and related costs	11,385	8,668
Total current liabilities	24,232	24,008
Noncurrent liabilities:
Accrued pension costs	13,875	14,155
Accrued postretirement benefits (OPEB) costs	2,617	2,773
Accrued environmental remediation and related costs	103,728	104,465
Deferred income taxes	27,031	25,035
Other	13,596	13,636
Total noncurrent liabilities	160,847	160,064
NL stockholders' equity:
Common stock	6,088	6,086
Additional paid-in capital	300,674	300,543
Retained earnings	87,055	88,679
Accumulated other comprehensive loss	(240,670)	(245,358)
Total NL stockholders' equity	153,147	149,950
Noncontrolling interest in subsidiary	15,755	15,301
Total equity	168,902	165,251
Total liabilities and equity	353,981	349,323
Commitments and contingencies (Notes 11 and 13)