Summary of Significant Accounting Policies Summary of Significant Accounting Policies - Disaggregated Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	$ 185,022
Realized loss on derivatives	(4,258)	$ (2,219)
Unrealized gain on derivatives	10,416	20,631
Total revenue	191,180	$ 134,814
Oil revenues
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	148,159
Natural gas revenues
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	33,795
Third-party midstream services revenues
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	3,068
Total revenues from contracts with customers
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	$ 185,022