Annual report pursuant to Section 13 and 15(d)

INCOME TAXES (Details)

v3.6.0.2
INCOME TAXES (Details) - USD ($)
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Provision for income taxes [Abstract]      
Current federal provision $ 1,691,000 $ 4,062,000 $ 8,756,000
Current state provision 18,000 285,000 296,000
Deferred federal provision (benefit) 8,645,000 5,367,000 (1,893,000)
Deferred state provision (benefit) 150,000 50,000 (12,000)
Income tax expense $ 10,504,000 $ 9,764,000 $ 7,147,000
Federal statutory rate 35.00% 35.00% 35.00%
Effective tax rate in income tax expense and the Federal statutory rate [Abstract]      
Income taxes at U.S. statutory rate $ 10,476,000 $ 9,927,000 $ 7,952,000
State taxes, net of federal benefit 285,000 230,000 181,000
Permanent and other items (257,000) (393,000) (915,000)
Increase (decrease) in valuation allowance 0 0 (71,000)
Income tax expense 10,504,000 9,764,000 7,147,000
Deferred tax liabilities [Abstract]      
Plant, pipeline and equipment (22,598,000) (14,996,000)  
Intangible assets (786,000) (284,000)  
Other assets (10,000) (14,000)  
Investment in AMAK (3,109,000) (2,522,000)  
Total deferred tax liabilities (26,503,000) (17,816,000)  
Deferred tax assets [Abstract]      
Accounts receivable 322,000 283,000  
Inventory 1,283,000 1,785,000  
Mineral interests 376,000 376,000  
Unrealized loss on swap agreements 20,000 62,000  
Post-retirement benefits 423,000 330,000  
Stock-based compensation 1,372,000 969,000  
Intangible assets 0 0  
Deferred revenue 0 0  
Gross deferred tax assets 3,796,000 3,805,000  
Valuation allowance (376,000) (376,000)  
Total net deferred tax assets 3,420,000 3,429,000  
Net deferred tax liabilities (23,083,000) (14,387,000)  
Current [Abstract]      
Deferred tax asset 1,615,000 2,116,000  
Non-current [Abstract]      
Deferred tax assets 6,124,000 4,637,000  
Deferred tax liability (30,446,000) (20,764,000)  
Valuation allowance (376,000) (376,000)  
Non-current deferred tax liability, net (24,698,000) (16,503,000)  
Net deferred tax liabilities (23,083,000) (14,387,000)  
Income tax expense or liability in Saudi Arabia 0 0 0
Income Tax Contingency [Line Items]      
Income tax expense 10,504,000 $ 9,764,000 $ 7,147,000
Federal and state tax authority [Member]      
Provision for income taxes [Abstract]      
Income tax expense 524,000    
Effective tax rate in income tax expense and the Federal statutory rate [Abstract]      
Income tax expense 524,000    
Income Tax Contingency [Line Items]      
Income tax expense $ 524,000