Bank Credit Facility (Details) (Credit facility [Member], USD $) In Millions, unless otherwise specified	6 Months Ended		9 Months Ended	6 Months Ended	2 Months Ended	6 Months Ended	9 Months Ended	6 Months Ended	9 Months Ended	6 Months Ended		9 Months Ended		6 Months Ended
	Jun. 30, 2012	Mar. 31, 2012	Mar. 31, 2013 Amendment of credit agreement [Member]	Jun. 30, 2012 Maximum [Member]	Nov. 30, 2013 Alternate Base Rate [Member]	Jun. 30, 2012 Alternate Base Rate [Member]	Mar. 31, 2013 Alternate Base Rate [Member] Amendment of credit agreement [Member]	Jun. 30, 2012 Alternate Base Rate [Member] Minimum [Member]	Mar. 31, 2013 Alternate Base Rate [Member] Minimum [Member]	Jun. 30, 2012 LIBOR [Member]	Jun. 30, 2012 LIBOR [Member] Minimum [Member]	Mar. 31, 2013 LIBOR [Member] Minimum [Member]	Jun. 30, 2012 LIBOR [Member] Maximum [Member]	Jun. 30, 2012 Federal Funds Rate [Member]	Jun. 30, 2012 Prime Rate [Member]	Jun. 30, 2012 One-month LIBOR [Member]
Bank Credit Facility (Textual)
Current borrowing base	$ 20.0
Maximum line of credit available under hedging arrangements				8.0
Number of consecutive fiscal quarters used for calculation of Funded Debt Ratio	4
Maximum borrowing base	50.0
Variable interest rate basis						Alternate Base Rate				LIBOR				Federal Funds Rate	Prime Rate	One-month LIBOR
Percentage points added to the reference rate						1.50%					2.50%		3.25%	0.50%		1.00%
Variable interest rate floor (as a percent)								4.50%	4.75%		4.50%	4.75%
Outstanding borrowings	13.8
Additional borrowing capacity available	$ 6.2
Effective borrowing rate (as a percent)		4.60%
Current ratio required to be maintained	1
EBITDAX multiplier of denominator for computation of funded debt ratio				4.0
Funded Debt Ratio required to be maintained				4.25
Percentage of increased points added to the reference rate					2.50%
Percentage of other increased credit spread added to the reference rate			0.25%				0.25%