Rates and Other Regulatory Activities - Additional Information (Detail) (USD $)	3 Months Ended			0 Months Ended	6 Months Ended
	Mar. 31, 2014	Mar. 31, 2014 Florida [Member]	Mar. 31, 2014 TETLP Expansion Project [Member] Eastern Shore [Member]	Jun. 13, 2013 White Oak Lateral Project Filing [Member] Eastern Shore [Member] mi in	Jun. 30, 2013 White Oak Lateral Project Filing [Member] Eastern Shore [Member]
Rates and Other Regulatory Activities [Line Items]
Reduction in accumulated depreciation	$ 4,500,000
Public Utilities, Interim Rate Increase (Decrease), Amount		2,400,000
Public Utilities, Requested Rate Increase (Decrease), Amount		5,900,000
Estimated Environmental Cleanup Costs To Be Recovered		381,000
Increase in Pipeline Capacity			57,000
Estimated capital cost					$ 11,200,000
White Oak lateral capacity of firm transportation service				55,200
White Oak lateral length of pipeline to be installed				5.5
Lateral diamater of pipeline to be installed				16
New plant capacity volume			107,000	55,200