Goodwill and Other Intangible Assets - Additional Information (Detail) (USD $)	12 Months Ended							12 Months Ended					12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Regulated Energy [Member]	Dec. 31, 2011 Regulated Energy [Member]	Dec. 31, 2012 Unregulated Energy [Member]	Dec. 31, 2011 Unregulated Energy [Member]	Dec. 31, 2012 FPU [Member]	Oct. 31, 2009 FPU [Member] Regulated Energy [Member]	Aug. 30, 2010 Indiantown Gas Company [Member] Regulated Energy [Member]	Dec. 31, 2011 Crescent Propane Inc [Member] Unregulated Energy [Member]	Dec. 31, 2012 Sharp Energy Inc [Member] Unregulated Energy [Member]	Dec. 31, 2012 Virginia LP Gas, Inc. [Member] Minimum [Member]	Dec. 31, 2012 Virginia LP Gas, Inc. [Member] Maximum [Member]
Goodwill [Line Items]
Goodwill	$ 4,090,000	$ 4,090,000		$ 3,216,000	$ 3,216,000	$ 874,000	$ 874,000		$ 2,500,000	$ 746,000	$ 200,000	$ 674,000
Amortized period of acquired intangible assets								12 years					7 years	40 years
Amortization of intangible assets	329,000	332,000	679,000
Amortization of intangible assets, 2013	325,000
Amortization of intangible assets, 2014	325,000
Amortization of intangible assets, 2015	325,000
Amortization of intangible assets, 2016	325,000
Amortization of intangible assets, 2017	$ 301,000