FAIR VALUE OF FINANCIAL INSTRUMENTS (Assets and Liabiliites Measured on a Nonrecurring Basis) (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Assets:
Cash		$ 18
Fair Value, Inputs, Level 1 [Member]
Assets:
Cash		18
Fair Value, Inputs, Level 1 [Member] | Carrying Amount
Assets:
Cash	$ 541,508	665,492
Fair Value, Inputs, Level 1 [Member] | Estimated Fair Value
Assets:
Cash	541,508	665,492
Fair Value, Inputs, Level 2 [Member] | Carrying Amount
Liabilities:
Fixed-rate debt	1,324,367	1,184,141
Variable-rate debt	1,447,125	1,524,319
Fair Value, Inputs, Level 2 [Member] | Estimated Fair Value
Liabilities:
Fixed-rate debt	1,316,391	1,224,573
Variable-rate debt	$ 1,447,125	$ 1,524,319