CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
NET INCOME (LOSS)	$ (239,447)	$ 119,597	$ (31,043)	$ 212,036
OTHER COMPREHENSIVE INCOME:
Net reclassification adjustment for amounts recognized in net income (loss) as a component of net periodic benefit cost, net of income tax expense of $1,854 and $1,313 for the three months ended September 30, 2015 and 2014, and $5,502 and $3,899 for the nine months ended September 30, 2015 and 2014, respectively	3,456	2,453	10,255	7,281
COMPREHENSIVE INCOME (LOSS)	$ (235,991)	$ 122,050	$ (20,788)	$ 219,317