ACCUMULATED OTHER COMPREHENSIVE LOSS (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance		$ (24,499)
Other comprehensive loss before reclassifications		63
Amounts reclassified from AOCL		37
Other Comprehensive Income - Net of Tax	[1]	100	$ 1
Ending balance		$ (24,399)
Combined statutory tax rate		40.00%	40.00%
Postretirement Liability Adjustment
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance		$ (22,145)
Other comprehensive loss before reclassifications		0
Amounts reclassified from AOCL		0
Other Comprehensive Income - Net of Tax		0
Ending balance		(22,145)
Unrealized Gain (Loss) on Derivatives-Other
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance		(2,129)
Other comprehensive loss before reclassifications		0
Amounts reclassified from AOCL		51
Other Comprehensive Income - Net of Tax		51
Ending balance		(2,078)
Unrealized Gain (Loss) on Available-for-Sale Securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance		(128)
Other comprehensive loss before reclassifications		63
Amounts reclassified from AOCL		(14)
Other Comprehensive Income - Net of Tax		49
Ending balance		(79)
Other Comprehensive Income (Loss) of Affiliated Companies
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance		(97)
Other comprehensive loss before reclassifications		0
Amounts reclassified from AOCL		0
Other Comprehensive Income - Net of Tax		0
Ending balance		$ (97)

[1] Determined using a combined average statutory tax rate of 40%.