FAIR VALUE MEASUREMENTS Assets Measured at Fair Value Subject to Three-Tier Hierarchy (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring Basis
Fair value, level transfers	$ 0	$ 0
Recurring Basis | Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis
Total - asset	37,441,000	36,838,000
Recurring Basis | Fair Value, Inputs, Level 1 | Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring Basis
Cash and cash equivalents	15,000	49,000
Recurring Basis | Fair Value, Inputs, Level 1 | Fixed Income Securities
Fair Value, Assets and Liabilities Measured on Recurring Basis
Mutual funds	36,357,000	35,813,000
Recurring Basis | Fair Value, Inputs, Level 1 | Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring Basis
Mutual funds	1,069,000	976,000
Recurring Basis | Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis
Total - net liability	(7,801,000)	(3,436,000)
Recurring Basis | Fair Value, Inputs, Level 2 | Interest Rate Swap
Fair Value, Assets and Liabilities Measured on Recurring Basis
Derivative assets	359,000	112,000
Derivative liabilities	$ (8,160,000)	$ (3,548,000)