Income Taxes (Details 3) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets [Abstract]
Property and equipment	$ 603,045	$ 776,504
Deferred gain on sale	40,867	44,593
U.S. federal tax credit carryforwards	15,967	16,144
U. S. net operating loss carryforwards	428,212	319,673
US state net operating loss carryforward	71,323	61,919
Non U.S. net operating loss carryforwards	30,211	9,142
Asset retirement obligations	55,700	51,815
Liabilities Subject To Compromise - Contract Settlement	59,166	0
Incentive compensation/other, net	16,088	28,711
Deferred tax assets noncurrent before valuation allowances	1,320,579	1,308,501
Valuation allowance	(1,270,935)	(1,307,076)
Net deferred tax assets	49,644	1,425
Deferred Tax Liabilities [Abstract]
Other	0	1,424
Liabilities Subject To Compromise - Interest	35,498	0
Liabilities Subject To Compromise - Interest Non US	14,146	0
Net tax liabilities	49,644	1,424
Net non-current tax liability	$ 0	$ 1