STOCKHOLDERS' EQUITY (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Unrecognized net periodic benefit costs:
INCOME (LOSS) BEFORE INCOME TAXES									$ 70,612	$ 19,461	$ (16,992)
Tax benefit	(5,097)	(12,938)	(10,163)	3,762	(3,549)	(7,022)	(2,987)	9,908	(24,435)	(3,650)	9,260
NET INCOME (LOSS)	14,543	19,618	17,208	(5,193)	10,346	13,982	4,878	(13,395)	46,177	15,811	(7,732)
Unrecognized Net Periodic Benefit Costs | Amounts Reclassified from Accumulated Other Comprehensive Loss
Unrecognized net periodic benefit costs:
Amortization of net actuarial loss									(2,705)	(7,935)
Amortization of prior service credit									190	190
Pension settlement expense									(6,595)	(2,111)
INCOME (LOSS) BEFORE INCOME TAXES									(9,110)	(9,856)
Tax benefit									3,544	3,835
NET INCOME (LOSS)									$ (5,566)	$ (6,021)