Summary of Significant Accounting Policies (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Summary of reconciliation of the ARO
Balance at beginning of period			$ 2,699	$ 2,321
Accretion expense	29	36	87	103
Additions assumed with consolidated partnerships			4	34
Additions during period			131	164
Balance at end of period	$ 2,921	$ 2,622	$ 2,921	$ 2,622