Income Taxes - Deferred Tax Assets Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets:
Net operating loss carryforwards	$ 1,826,656	$ 1,510,354
Equity compensation	36,972	37,633
Deferred revenue	31,082	19,422
Tax credit and other attribute carryforwards	91,680	119,471
Insurance loss reserve	5,118	6,192
Accrued interest	357,285	288,687
Other	115,909	135,185
Subtotal	2,464,702	2,116,944
Valuation allowance	(1,807,728)	(1,560,162)
Deferred tax assets	656,974	556,782
Deferred tax liabilities:
Depreciation, amortization for tax in excess of book expense	288,086	384,513
Variable interest investments	641	718
Other	11,154	16,009
Deferred tax liability	299,881	401,240
Net deferred tax assets	357,093	155,542
Balance Sheet Summary :
Net noncurrent deferred asset	366,588	184,868
Net current deferred liability	(9,495)	(29,326)
Net noncurrent deferred liability	$ (9,495)	$ (29,326)