NOTES PAYABLE TO BANKS - Interest incurred on credit facility, interest capitalized related to facilities and equipment under construction, and related weighted average interest rates (Details) (Revolving credit facility, USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Revolving credit facility
Line of Credit Facility [Line Items]
Interest incurred	$ 594	$ 923
Capitalized interest	$ 241	$ 321
Weighted average interest rate	3.00%	2.10%