FRESH START ACCOUNTING - Cumulative Impact of the Reorganization Adjustments (Details) - Exchange of Stock for Stock $ in Thousands	Feb. 28, 2017 USD ($)
Fresh-Start Adjustment [Line Items]
Gain on settlement of liabilities subject to compromise	$ 230,554
Professional and other fees paid at emergence	(10,648)
Write-off of unamortized deferred financing costs	(2,577)
Other reorganization adjustments	(1,915)
Net impact to reorganization items	215,414
Gain on sale of Appalachia Properties	213,453
Cancellation of Predecessor Company equity	1,662,282
Other adjustments to accumulated deficit	(17,165)
Net impact to accumulated deficit	$ 2,073,984