FAIR VALUE MEASUREMENTS (Details) - Recurring Measurements [Member] - USD ($) $ in Thousands		Mar. 31, 2016	Dec. 31, 2015
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total
Level 1 [Member] | Executive Retirement Program Liability [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Executive retirement liability
Level 1 [Member] | Crude Oil Derivatives Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Crude oil price risk derivatives
Level 1 [Member] | Equity Securities [Member] | Sutter Gold Mining Company [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable equity securitites
Level 1 [Member] | Equity Securities [Member] | Anfield Resources, Inc. [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable equity securitites	[1]
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total		$ 1,084	$ 1,647
Level 2 [Member] | Executive Retirement Program Liability [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Executive retirement liability
Level 2 [Member] | Crude Oil Derivatives Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Crude oil price risk derivatives		$ 1,061	$ 1,634
Level 2 [Member] | Equity Securities [Member] | Sutter Gold Mining Company [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable equity securitites		$ 23	$ 13
Level 2 [Member] | Equity Securities [Member] | Anfield Resources, Inc. [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable equity securitites	[1]
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total		$ 238	$ 238
Level 3 [Member] | Executive Retirement Program Liability [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Executive retirement liability			$ 584
Level 3 [Member] | Crude Oil Derivatives Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Crude oil price risk derivatives
Level 3 [Member] | Equity Securities [Member] | Sutter Gold Mining Company [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable equity securitites
Level 3 [Member] | Equity Securities [Member] | Anfield Resources, Inc. [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable equity securitites	[1]	$ 238	$ 238
Total [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total		$ 1,322	1,885
Total [Member] | Executive Retirement Program Liability [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Executive retirement liability			584
Total [Member] | Crude Oil Derivatives Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Crude oil price risk derivatives		$ 1,061	1,634
Total [Member] | Equity Securities [Member] | Sutter Gold Mining Company [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable equity securitites		23	13
Total [Member] | Equity Securities [Member] | Anfield Resources, Inc. [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable equity securitites	[1]	$ 238	$ 238

[1] Because of limited trading for this investment and considering the large block of common stock held by the Company, management determined that the quoted marked price was not an accurate indicator of fair value. Accordingly, the Company used alternative methods to determine fair value upon receipt of the shares in September 2015, which requires classification under Level 3 of the fair value hierarchy.