Subsequent Events (Details) $ in Millions	3 Months Ended
	Sep. 30, 2017 USD ($) a Boe	Jun. 30, 2016 USD ($)	Apr. 29, 2016 a
Subsequent Event [Line Items]
Proceeds from Sale of Oil and Gas Property and Equipment		$ 110.0
Leasehold | a			132,000
Subsequent Event [Member]
Subsequent Event [Line Items]
Proceeds from Sale of Oil and Gas Property and Equipment	$ 147.5
Leasehold | a	32,600
Production, Barrels of Oil Equivalents | Boe	1,800
Gain (Loss) on Disposition of Assets	$ 65.0