Commitments And Contingencies (Details) (USD $)	1 Months Ended			3 Months Ended
	Aug. 31, 2010	Mar. 31, 2007	May 31, 2004	Mar. 31, 2012 Y	Mar. 30, 2007	Jun. 30, 2005
Commitments And Contingencies [Abstract]
Investigation review bids maximum (per MW)			$ 250
Owners percentage interest					15.00%
Number of families that own property near the holding ponds who filed a complaint		2
Number of years, license issued				50
Accrual for environmental loss contingencies						$ 500,000
Number of hydroelectric plants				6
Number of diversion tunnels				2
Number of residences destroyed	2
Number of outbuildings destroyed	6