Annual report pursuant to Section 13 and 15(d)

INVESTMENT IN AL MASANE AL KOBRA MINING COMPANY ("AMAK") (Details)

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INVESTMENT IN AL MASANE AL KOBRA MINING COMPANY ("AMAK") (Details)
3 Months Ended 12 Months Ended
Jul. 31, 2016
$ / shares
shares
Sep. 30, 2016
USD ($)
Dec. 31, 2017
USD ($)
ر.س / $
Dec. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Jul. 31, 2016
ر.س / shares
shares
Jul. 10, 2016
Jul. 09, 2016
Schedule of Equity Method Investments [Line Items]                
Exchange rate | ر.س / $     3.75          
Results of Operations [Abstract]                
Operating income     $ 18,102,000 $ 18,707,000 $ 36,041,000      
Equity in Income or Loss of AMAK Reflected on Consolidated Statement Of Operation [Abstract]                
Equity in loss of AMAK     (4,261,000) (1,479,000) (5,325,000)      
Shares issued (in shares) | shares 4,000,000              
Gain from equity issuance by AMAK   $ 3,200,000 0 3,168,000 0      
AMAK [Member]                
Schedule of Equity Method Investments [Line Items]                
Investment in AMAK     $ 45,100,000 49,400,000        
Exchange rate | ر.س / $     3.75          
Results of Operations [Abstract]                
Sales     $ 36,435,000 9,921,000 50,744,000      
Gross loss     (6,869,000) (17,211,000) (10,437,000)      
General, administrative and other expenses     9,903,000 9,690,000 8,796,000      
Operating income     (16,772,000) (26,901,000) (19,233,000)      
Gain on settlement with former operator     0 17,425,000 0      
Net loss     (16,772,000) (9,476,000) (19,233,000)      
Depreciation and amortization expense     22,400,000 11,700,000 23,200,000      
Net income before depreciation and amortization     5,647,000 2,196,000 4,016,000      
Financial Position [Abstract]                
Current assets     23,333,000 22,860,000        
Noncurrent assets     237,875,000 251,741,000        
Total assets     261,208,000 274,601,000        
Current liabilities     24,439,000 8,005,000        
Long term liabilities     68,837,000 82,546,000        
Shareholders' equity     167,932,000 184,050,000        
Total liabilities and equity     261,208,000 274,601,000        
Equity in Income or Loss of AMAK Reflected on Consolidated Statement Of Operation [Abstract]                
AMAK Net income (loss)     (16,772,000) (9,476,000) (19,233,000)      
Zakat tax applicable to Saudi Arabian shareholders only     0 320,000 303,000      
AMAK Net Loss before Saudi Arabian shareholders' portion of Zakat     (16,772,000) (9,156,000) (18,930,000)      
Company's share of loss reported by AMAK (33.44% beginning July 10, 2016 and 35.25% prior to July 10, 2016)     (5,608,000) (2,826,000) (6,672,000)      
Amortization of difference between Company's investment in AMAK and Company's share of net assets of AMAK     1,347,000 1,347,000 1,347,000      
Equity in loss of AMAK     (4,261,000) (1,479,000) (5,325,000)      
Gain upon formation of AMAK     $ 16,200,000          
Shares issued (in shares) | shares 4,000,000              
Percentage investment in AMAK     100.00%       33.44% 35.25%
Gain from equity issuance by AMAK     $ 3,200,000          
Amount receivable for unreimbursed travel expenses     121,000          
Impairment charges on investment in AMAK     $ 0 $ 0 $ 0      
AMAK [Member] | Various Saudi Shareholders [Member]                
Equity in Income or Loss of AMAK Reflected on Consolidated Statement Of Operation [Abstract]                
Percentage investment in AMAK     46.73%          
AMAK [Member] | Trecora Resources [Member]                
Equity in Income or Loss of AMAK Reflected on Consolidated Statement Of Operation [Abstract]                
Percentage investment in AMAK     33.44%          
AMAK [Member] | Armico [Member]                
Equity in Income or Loss of AMAK Reflected on Consolidated Statement Of Operation [Abstract]                
Percentage investment in AMAK     19.83%          
Arab Mining Co [Member]                
Equity in Income or Loss of AMAK Reflected on Consolidated Statement Of Operation [Abstract]                
Shares issued (in shares) | shares 3,750,000              
Share price (in dollars per share) | (per share) $ 5.33         ر.س 20.00    
Shares reserved for future issuance (in shares) | shares 250,000         250,000