Additional Balance Sheet Details (Details 1) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Accounts Payable and Accrued Liabilities, Current [Abstract]
Accrued interest	$ 48,908	$ 48,255
Accrued compensation	46,780	62,513
Accrued lease operating expenses	37,549	56,798
Taxes payable	32,438	39,816
Accounts payable	30,477	64,604
Accrued exploration and development costs	20,892	90,939
Other	36,153	31,833
Total	$ 253,197	$ 394,758