Commitments and Contingencies (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012 MMcf
Gross Volume Information
Oil and Gas Delivery Commitments (MMcf)	471,881
Dollar commitment (in thousands)	$ 199,184
Twelve Months Ending June 30, 2013
Gross Volume Information
Oil and Gas Delivery Commitments (MMcf)	40,946
Dollar commitment (in thousands)	19,161
Twelve Months Ending June 30, 2014
Gross Volume Information
Oil and Gas Delivery Commitments (MMcf)	61,891
Dollar commitment (in thousands)	30,197
Twelve Months Ending June 30, 2015
Gross Volume Information
Oil and Gas Delivery Commitments (MMcf)	57,887
Dollar commitment (in thousands)	27,430
Twelve Months Ending June 30, 2016
Gross Volume Information
Oil and Gas Delivery Commitments (MMcf)	54,479
Dollar commitment (in thousands)	25,098
Twelve Months Ending June 30, 2017 Through Expiration
Gross Volume Information
Oil and Gas Delivery Commitments (MMcf)	256,678
Dollar commitment (in thousands)	$ 97,298
Piceance Basin
Gross Volume Information
Oil and Gas Delivery Commitments (MMcf)	218,504
Piceance Basin | Twelve Months Ending June 30, 2013
Gross Volume Information
Oil and Gas Delivery Commitments (MMcf)	19,740
Piceance Basin | Twelve Months Ending June 30, 2014
Gross Volume Information
Oil and Gas Delivery Commitments (MMcf)	39,259
Piceance Basin | Twelve Months Ending June 30, 2015
Gross Volume Information
Oil and Gas Delivery Commitments (MMcf)	33,207
Piceance Basin | Twelve Months Ending June 30, 2016
Gross Volume Information
Oil and Gas Delivery Commitments (MMcf)	28,127
Piceance Basin | Twelve Months Ending June 30, 2017 Through Expiration
Gross Volume Information
Oil and Gas Delivery Commitments (MMcf)	98,171
Piceance Basin | Supply Contract Expiration Date [Member]
Gross Volume Information
Expiration Date	May 31, 2021
Appalachiain Basin
Gross Volume Information
Oil and Gas Delivery Commitments (MMcf)	244,247	[1]
Appalachiain Basin | Twelve Months Ending June 30, 2013
Gross Volume Information
Oil and Gas Delivery Commitments (MMcf)	18,466	[1]
Appalachiain Basin | Twelve Months Ending June 30, 2014
Gross Volume Information
Oil and Gas Delivery Commitments (MMcf)	20,807	[1]
Appalachiain Basin | Twelve Months Ending June 30, 2015
Gross Volume Information
Oil and Gas Delivery Commitments (MMcf)	22,855	[1]
Appalachiain Basin | Twelve Months Ending June 30, 2016
Gross Volume Information
Oil and Gas Delivery Commitments (MMcf)	24,527	[1]
Appalachiain Basin | Twelve Months Ending June 30, 2017 Through Expiration
Gross Volume Information
Oil and Gas Delivery Commitments (MMcf)	157,592	[1]
Appalachiain Basin | Supply Contract Expiration Date [Member]
Gross Volume Information
Expiration Date	Sep. 30, 2025	[1]
NECO
Gross Volume Information
Oil and Gas Delivery Commitments (MMcf)	9,130
NECO | Twelve Months Ending June 30, 2013
Gross Volume Information
Oil and Gas Delivery Commitments (MMcf)	2,740
NECO | Twelve Months Ending June 30, 2014
Gross Volume Information
Oil and Gas Delivery Commitments (MMcf)	1,825
NECO | Twelve Months Ending June 30, 2015
Gross Volume Information
Oil and Gas Delivery Commitments (MMcf)	1,825
NECO | Twelve Months Ending June 30, 2016
Gross Volume Information
Oil and Gas Delivery Commitments (MMcf)	1,825
NECO | Twelve Months Ending June 30, 2017 Through Expiration
Gross Volume Information
Oil and Gas Delivery Commitments (MMcf)	915
NECO | Supply Contract Expiration Date [Member]
Gross Volume Information
Expiration Date	Dec. 31, 2016

[1] (1)Includes a precedent agreement that becomes effective when a planned pipeline is placed in service, currently expected to be September 2012, and represents 8,822 MMcf of the total MMcf presented for the twelve months ending June 30, 2013, 10,627 MMcf for each of the twelve months ending June 30, 2014 through 2016 and 31,882 MMcf thereafter. This agreement will be null and void if the pipeline is not completed. In August 2009, we issued a letter of credit related to this agreement. See Note 7.