Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Successor
Net income (loss)	$ 68,351		$ 157,179
Derivative instruments
Comprehensive income (loss) before tax	(19)		257
Income tax benefit (provision)	0		0
Derivatives qualifying as hedges, adjustment, net of tax	(19)		257
Pension, postretirement and other post-employment benefits
Comprehensive income (loss) before tax	(8,521)		(5,367)
Income tax benefit (provision)	0		0
Pension and other postretirement benefit plans, adjustment, net of tax	(8,521)		(5,367)
Available-for-sale securities
Comprehensive income (loss) before tax	0		(387)
Income tax benefit (provision)	0		0
Available-for-sale securities adjustment, net of tax	0		(387)
Total other comprehensive income (loss)	(8,540)		(5,497)
Total comprehensive income (loss)	$ 59,811		$ 151,682
Predecessor
Net income (loss)		$ (51,421)		$ (434,010)
Derivative instruments
Comprehensive income (loss) before tax		(149)		(535)
Income tax benefit (provision)		0		81
Derivatives qualifying as hedges, adjustment, net of tax		(149)		(454)
Pension, postretirement and other post-employment benefits
Comprehensive income (loss) before tax		2,243		(1,844)
Income tax benefit (provision)		0		481
Pension and other postretirement benefit plans, adjustment, net of tax		2,243		(1,363)
Available-for-sale securities
Comprehensive income (loss) before tax		(438)		2,969
Income tax benefit (provision)		0		(1,043)
Available-for-sale securities adjustment, net of tax		(438)		1,926
Total other comprehensive income (loss)		1,656		109
Total comprehensive income (loss)		$ (49,765)		$ (433,901)