Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies (Narrative) (Details)

v3.6.0.2
Summary of Significant Accounting Policies (Narrative) (Details)
$ in Thousands
 3 Months Ended 12 Months Ended
Jun. 30, 2016
USD ($)
Mar. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Sep. 30, 2015
USD ($)
Dec. 31, 2016
USD ($)
$ / bbl
$ / Mcfe
Dec. 31, 2015
USD ($)
$ / bbl
$ / Mcfe
Dec. 31, 2014
USD ($)
Accounting Policies [Line Items]              
Write-down of oil and natural gas properties $ 61,012 $ 34,776 $ 121,134 $ 87,301 $ 95,788 $ 208,435  
Capitalized interest         19,857 10,459 $ 4,295
Amortization of financing costs         3,115 3,123 1,272
Deferred financing costs related to the senior secured revolving credit facility     3,642   3,092 3,642  
Deferred tax assets, valuation allowance     108,843   $ 140,192 $ 108,843  
Crude Oil [Member]              
Accounting Policies [Line Items]              
Prices used in determining estimated future net cash flows from proved reserves | $ / bbl         42.75 50.16  
Natural Gas [Member]              
Accounting Policies [Line Items]              
Prices used in determining estimated future net cash flows from proved reserves | $ / Mcfe         2.48 2.64  
Other Property and Equipment [Member]              
Accounting Policies [Line Items]              
Depreciation         $ 793 $ 865 $ 836
Accumulated depreciation     $ 14,719   $ 15,227 $ 14,719  
Other Property and Equipment [Member] | Minimum [Member]              
Accounting Policies [Line Items]              
Estimated useful lives of other property and equipment         3 years    
Other Property and Equipment [Member] | Maximum [Member]              
Accounting Policies [Line Items]              
Estimated useful lives of other property and equipment         20 years    
Options [Member]              
Accounting Policies [Line Items]              
Vesting period         3 years    
RSUs [Member]              
Accounting Policies [Line Items]              
Vesting period         3 years    
Cash-settleable RSU awards [Member]              
Accounting Policies [Line Items]              
Vesting period         3 years