Income Taxes (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Valuation Allowance [Line Items]
Effective income tax rate, percent	2.10%
Federal statutory income tax rate, percent	35.00%
Current income tax receivable	$ 46,174	$ 46,174
Income taxes receivable, noncurrent	3,200
Ceiling Test Write Downs From Decline in Commodity Prices
Valuation Allowance [Line Items]
Valuation allowance	$ 322,800