FAIR VALUE MEASUREMENTS (Textuals) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012
Laramie, Wyoming and Greeley, Colorado [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets held for sale	$ 4,102
Enid, Oklahoma [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets held for sale	$ 867