Chapter 11 Proceedings - Components of Liabilities Subject to Compromise (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2017 USD ($)
Liabilities Subject To Compromise [Abstract]
Liabilities subject to compromise at December 31, 2016	$ 4,038,041
Debt extinguishment - cash	(2,521,493)
Debt extinguishment - non-cash	(1,339,740)
Contract settlement	(169,600)
Reclassified to accrued liabilities	(7,208)
Liabilities subject to compromise at September 30, 2017	$ 0