Pending Acquisition and Acreage Exchanges Pending Acquisition and Acreage Exchange (Details)	9 Months Ended
	Sep. 30, 2017 USD ($) a Wells
Bayswater Acquisition [Member]
Property, Plant and Equipment
Gas and Oil Area, Developed, Net	8,300
Drilled Uncompleted Wells	30
Gas and Oil Area, Developed, Gross | Wells	240
Other Payments to Acquire Businesses | $	$ 210,000,000
Q4 2017 Drilled Uncompleted Wells	18
Other Payments to Acquire Businesses | $	$ 21,000,000
Third Party 2 acreage to PDC [Member]
Property, Plant and Equipment
Gas and Oil Area, Developed, Net	11,700
PDC acreage to Third Party 2 [Member]
Property, Plant and Equipment
Gas and Oil Area, Developed, Net	12,100
Third Party 1 acreage to PDC
Property, Plant and Equipment
Gas and Oil Area, Developed, Net	3,900
PDC acreage to Third Party 1
Property, Plant and Equipment
Gas and Oil Area, Developed, Net	4,100