Income Taxes (Components of Deferred Tax Assets and Liabilities) (Details 1) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Research and development credits	$ 21,600
Deferred tax assets
Loss carryforwards - federal	52,580	$ 44,076
Loss carryforwards - state	37,175	43,270
Tax credit carryover	34,837	34,837
Business credit carryforwards	70,452	42,817
Stock-based compensation	23,468	29,994
Other	34,236	32,656
Valuation Allowance	(33,600)	0
Total deferred tax assets	219,148	227,650
Deferred tax liabilities
Property and equipment	(1,004,330)	(2,806,850)
Derivative contracts	(50,081)	(185,385)
Other	(16,826)	(11,984)
Total deferred tax liabilities	(1,071,237)	(3,004,219)
Total net deferred tax liability	$ (852,089)	$ (2,776,569)