Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Successor [Member]
Net income (loss)	$ 51,668
Derivative instruments
Comprehensive income (loss) before tax	19
Income tax benefit (provision)	0
Derivatives qualifying as hedges, adjustment, net of tax	19
Pension, postretirement and other post-employment benefits
Comprehensive income (loss) before tax	0
Income tax benefit (provision)	0
Pension and other postretirement benefit plans, adjustment, net of tax	0
Available-for-sale securities
Comprehensive income (loss) before tax	(387)
Income tax benefit (provision)	0
Available-for-sale securities adjustment, net of tax	(387)
Total other comprehensive income (loss)	(368)
Total comprehensive income (loss)	$ 51,300
Predecessor [Member]
Net income (loss)		$ (206,702)
Derivative instruments
Comprehensive income (loss) before tax		(224)
Income tax benefit (provision)		81
Derivatives qualifying as hedges, adjustment, net of tax		(143)
Pension, postretirement and other post-employment benefits
Comprehensive income (loss) before tax		(1,338)
Income tax benefit (provision)		481
Pension and other postretirement benefit plans, adjustment, net of tax		(857)
Available-for-sale securities
Comprehensive income (loss) before tax		2,903
Income tax benefit (provision)		(1,043)
Available-for-sale securities adjustment, net of tax		1,860
Total other comprehensive income (loss)		860
Total comprehensive income (loss)		$ (205,842)