Subsequent Event (Details) - USD ($) $ in Thousands		1 Months Ended	6 Months Ended
	May 01, 2018	Oct. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Subsequent Event [Line Items]
Oil and Gas Producing Properties Purchase and Sale Agreement Price		$ 43,000
Net Proceeds from Sale of Oil and Gas Producing Properties			$ 17,310	$ 26,554
Subsequent Event [Member]
Subsequent Event [Line Items]
Net Proceeds from Sale of Oil and Gas Producing Properties	$ 38,300