Regulatory Matters - Summary of Utilities Rate Plans (Pike - Electric) (Detail) - Electric - Pike County Light & Power Company (Pike) - USD ($) $ in Thousands	12 Months Ended	65 Months Ended
	Aug. 31, 2015	Aug. 31, 2014
Public Utilities, General Disclosures [Line Items]
Base rate changes	$ 1,250	$ 900
Year 1
Public Utilities, General Disclosures [Line Items]
Amortization to income of net regulatory (assets) and liabilities	(70)	100
Year 2
Public Utilities, General Disclosures [Line Items]
Amortization to income of net regulatory (assets) and liabilities	(70)	100
Year 3
Public Utilities, General Disclosures [Line Items]
Amortization to income of net regulatory (assets) and liabilities	(70)	100
Year 4
Public Utilities, General Disclosures [Line Items]
Amortization to income of net regulatory (assets) and liabilities	(70)	100
Year 5
Public Utilities, General Disclosures [Line Items]
Amortization to income of net regulatory (assets) and liabilities	$ (70)	$ 100