Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 67,252	$ 15,334
Restricted cash	65	64
Trade accounts receivable, net of allowance for doubtful accounts	64,078	111,194
Inventories	76,658	80,473
Current assets associated with discontinued operations	710,006	127,341
Prepaid expenses and other current assets	13,487	16,948
Total current assets	931,546	351,354
Property, plant, and equipment:
Land and building	26,506	25,461
Machinery and equipment	365,296	358,688
Automobiles and trucks	18,446	22,476
Chemical plants	62,714	57,692
Construction in progress	1,526	7,408
Total property, plant, and equipment	474,488	471,725
Less accumulated depreciation	(377,632)	(355,455)
Net property, plant, and equipment	96,856	116,270
Other assets:
Patents, trademarks, and other intangible assets, net of accumulated amortization	41,487	46,182
Deferred tax assets, net	52	0
Operating lease right-of-use assets	43,448	47,125
Other assets	19,450	15,633
Long-term assets associated with discontinued operations (1)	0	695,358
Total other assets	104,437	804,298
Total assets	1,132,839	1,271,922
Current liabilities:
Trade accounts payable	22,573	41,080
Unearned income	2,675	326
Accrued liabilities	38,791	44,855
Current liabilities associated with discontinued operations (1)	734,039	102,462
Total current liabilities	798,078	188,723
Long-term debt, net	199,894	204,633
Deferred income taxes	1,942	1,777
Asset retirement obligations	12,484	12,762
Warrants liability	198	449
Operating lease liabilities	37,569	40,097
Other liabilities	11,612	7,351
Long-term liabilities associated with discontinued operations (1)	0	653,304
Total long-term and other liabilities	263,699	920,373
Equity:
Common stock, par value $.01 per share; 100,000,000 shares authorized; 83,013,971 shares issued at December 31, 2015, and 82,322,876 shares issued at December 31, 2014	1,289	1,283
Additional paid-in capital	472,134	466,959
Treasury stock, at cost; 2,766,958 shares held at December 31, 2015, and 2,672,930 shares held at December 31, 2014	(19,484)	(19,164)
Accumulated other comprehensive income (loss)	(49,914)	(52,183)
Retained earnings	(413,665)	(362,522)
Total TETRA stockholders' equity	(9,640)	34,373
Noncontrolling interest	80,702	128,453
Total equity	71,062	162,826
Total liabilities and equity	$ 1,132,839	$ 1,271,922