Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement of Comprehensive Income [Abstract]
Net Income (Loss)	$ 53,314	$ (227,904)	$ (113,043)	$ (354,925)
Pension and postretirement plans:
Amortization of prior service cost, net of tax of ($43), $0, ($133) and $0, respectively	(71)	0	(219)	0
Amortization of net loss, including settlement charges, net of tax of $0, $256, $1,168 and $1,561, respectively	0	474	1,890	2,901
Current period change in fair value of pension and postretirement plans, net of tax of $0, $0, ($6) and $0, respectively	0	0	(9)	0
Total pension and postretirement plans	(71)	474	1,662	2,901
Comprehensive Income (Loss)	$ 53,243	$ (227,430)	$ (111,381)	$ (352,024)