Long-Term Debt (Details)	6 Months Ended		12 Months Ended
	Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)	May 19, 2016 USD ($)
Line of Credit Facility [Line Items]
Amortization of debt issuance costs	$ 246,000	$ 324,000
Unamortized debt issue costs	1,900,000		$ 2,100,000
Credit Agreement [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity	500,000,000
Sub-limit which may be used for issuance of letters of credit	$ 15,000,000
Borrowing base amount				$ 200,000,000
Exceeding of reserve-based credit facility over borrowing base (as a percent)	90.00%
Credit Agreement [Member] | Second full quarter after Catarina acquisition
Line of Credit Facility [Line Items]
Borrowing base multiplier	4.75
Credit Agreement [Member] | Thereafter
Line of Credit Facility [Line Items]
Borrowing base multiplier	4.5
Minimum | Credit Agreement [Member]
Line of Credit Facility [Line Items]
Commitment fee on unutilized borrowing base	0.375%
Consolidated current asset ratio	1.0
Required interest coverage ratio	2.5
Minimum | Credit Agreement [Member] | Scenario One [Member]
Line of Credit Facility [Line Items]
Debt to Adjusted EBITDA ratio	4.5
Minimum | Credit Agreement [Member] | Scenario Two [Member]
Line of Credit Facility [Line Items]
Debt to Adjusted EBITDA ratio	4.0
Minimum | Credit Agreement [Member] | London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Facility [Line Items]
Variable interest rate	1.75%
Minimum | Credit Agreement [Member] | ABR [Member]
Line of Credit Facility [Line Items]
Variable interest rate	0.75%
Maximum | Credit Agreement [Member]
Line of Credit Facility [Line Items]
Commitment fee on unutilized borrowing base	0.50%
Maximum | Credit Agreement [Member] | London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Facility [Line Items]
Variable interest rate	2.75%
Maximum | Credit Agreement [Member] | ABR [Member]
Line of Credit Facility [Line Items]
Variable interest rate	1.75%
Accounting Standards Update 2015-03 | Scenario, Adjustment
Line of Credit Facility [Line Items]
Long term debt, net of debt issuance costs			(2,091,000)
Amortization of debt issuance costs			$ (2,091,000)