Summary of Significant Accounting Policies (Details Textual)	12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 31, 2017 USD ($) shares	Dec. 31, 2017 USD ($) Purchasers	Dec. 31, 2017 USD ($) $ / bbl	Dec. 31, 2017 USD ($) $ / MMBTU	Dec. 31, 2017 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 shares	Dec. 31, 2016 Purchasers	Dec. 31, 2016 $ / bbl	Dec. 31, 2016 $ / MMBTU	Dec. 31, 2016	Dec. 31, 2016 USD ($)	Dec. 31, 2015 shares	Dec. 31, 2015 Purchasers	Dec. 31, 2015 $ / bbl	Dec. 31, 2015 $ / MMBTU	Dec. 31, 2015	Dec. 31, 2015 USD ($)
Summary of Significant Accounting Policies [Line Items]
Billing date	30 days
Outstanding days of account receivable	60 days
Allowance for doubtful accounts	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0
Capitalized general and administrative costs							23,100,000						$ 15,700,000						$ 6,900,000
Capitalized interest expense							7,300,000						3,700,000						3,900,000
Present value discounted percent of future net revenues of proved oil and natural gas reserves						10.00%
Average oil and natural gas prices				47.79	2.98					39.25	2.48					46.79	2.59
Impairment charge of net capitalized costs							0						158,633,000						801,166,000
Number of purchasers | Purchasers			4						3						3
Stock-based compensation (non-cash) expense							16,654,000						12,362,000						9,450,000
Common stock and restricted stock unit expense							3,000,000						1,000,000						900,000
Accelerated compensation cost							1,500,000
Percentage being realized up on ultimate settlement						50.00%
Machinery and Equipment [Member]
Summary of Significant Accounting Policies [Line Items]
Useful life using the straight-line	30 years
Maximum [Member]
Summary of Significant Accounting Policies [Line Items]
Accounts receivable due period	60 days
Useful life	30 years
Minimum [Member]
Summary of Significant Accounting Policies [Line Items]
Accounts receivable due period	30 days
Useful life	5 years
Accounts Receivable [Member]
Summary of Significant Accounting Policies [Line Items]
Concentration risk, percentage						43.00%						38.00%						39.00%
Sales Revenue, Goods, Net [Member]
Summary of Significant Accounting Policies [Line Items]
Concentration risk, percentage						60.00%						48.00%						59.00%
Stock options [Member]
Summary of Significant Accounting Policies [Line Items]
Stock-based compensation (non-cash) expense							$ 7,100,000						$ 5,900,000						$ 4,700,000
Restricted Stock Units (RSUs) [Member]
Summary of Significant Accounting Policies [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount | shares								90,552						73,923
Restricted stock [Member]
Summary of Significant Accounting Policies [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount | shares								1,039,292						854,238
Stock options [Member]
Summary of Significant Accounting Policies [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount | shares		1,000,000						2,886,821						2,362,861
Plains Marketing [Member] | Customer Concentration Risk [Member] | Sales Revenue, Goods, Net [Member]
Summary of Significant Accounting Policies [Line Items]
Concentration risk, percentage						14.00%						18.00%
Shell Trading (US) Company [Member] | Customer Concentration Risk [Member] | Sales Revenue, Goods, Net [Member]
Summary of Significant Accounting Policies [Line Items]
Concentration risk, percentage						12.00%						17.00%						33.00%
Western Refining Oil [Member] | Customer Concentration Risk [Member] | Sales Revenue, Goods, Net [Member]
Summary of Significant Accounting Policies [Line Items]
Concentration risk, percentage						11.00%
Occidental Energy Marketing [Member] | Customer Concentration Risk [Member] | Sales Revenue, Goods, Net [Member]
Summary of Significant Accounting Policies [Line Items]
Concentration risk, percentage						23.00%						13.00%
Enterprise Crude Oil LLC [Member] | Customer Concentration Risk [Member] | Sales Revenue, Goods, Net [Member]
Summary of Significant Accounting Policies [Line Items]
Concentration risk, percentage																		14.00%
Sequent Energy Management [Member] | Customer Concentration Risk [Member] | Sales Revenue, Goods, Net [Member]
Summary of Significant Accounting Policies [Line Items]
Concentration risk, percentage																		12.00%