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	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Line of Credit Facility [Line Items]
Interest incurred	$ 110	$ 518	$ 219	$ 1,363
Capitalized interest		$ 131		$ 310
Weighted average interest rate		2.32%		1.80%