ACCUMULATED OTHER COMPREHENSIVE LOSS (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	[1]	$ (30,257)		$ (30,258)
Other comprehensive income before reclassifications		(43)		49
Amounts reclassified from AOCL	[2]	149		58
Other Comprehensive Income - Net of Tax	[3]	106	$ 138	107	$ 248
Ending balance	[1]	(30,151)		$ (30,151)
Combined statutory tax rate				40.00%	41.00%
Postretirement Liability Adjustment
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	[1]	(27,663)		$ (27,663)
Other comprehensive income before reclassifications		0		0
Amounts reclassified from AOCL	[2]	0		0
Other Comprehensive Income - Net of Tax		0		0
Ending balance	[1]	(27,663)		(27,663)
Unrealized Gain (Loss) on Derivatives-Other
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	[1]	(2,442)		(2,450)
Other comprehensive income before reclassifications		0		0
Amounts reclassified from AOCL	[2]	111		119
Other Comprehensive Income - Net of Tax		111		119
Ending balance	[1]	(2,331)		(2,331)
Unrealized Gain (Loss) on Available-for-Sale Securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	[1]	13		(75)
Other comprehensive income before reclassifications		(43)		49
Amounts reclassified from AOCL	[2]	(21)		(25)
Other Comprehensive Income - Net of Tax		(64)		24
Ending balance	[1]	(51)		(51)
Other Comprehensive Income (Loss) of Affiliated Companies
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	[1]	(165)		(70)
Other comprehensive income before reclassifications		0		0
Amounts reclassified from AOCL	[2]	59		(36)
Other Comprehensive Income - Net of Tax		59		(36)
Ending balance	[1]	$ (106)		$ (106)

[1] For 2015, determined using a combined average statutory tax rate of 40%. For 2014, determined using a combined statutory tax rate of 41%.

[2] See table below.

[3] For 2015, determined using a combined average statutory tax rate of 40%. For 2014, determined using a combined statutory tax rate of 41%.