Blount Station (Details) (USD $)	9 Months Ended		12 Months Ended
	Sep. 30, 2011 MW Tons Dth MWh	Sep. 30, 2010	Dec. 31, 2011
Blount Capacity Megawatts [Abstract]
Blount capacity current - MW	190
Blount capacity future - MW	100
Blount capacity reduction - MW	90
Restructuring and related costs [Abstract]
Benefits expected to be paid			$ 400,000
Restructuring accrual activity [Roll forward]
Balance at December 31, 2010	259,000		259,000
Additional expense, net	106,000
Cash payments during the period	(24,000)
Ending balance	341,000
Accelerated Depreciation Recovered [Abstract]
Accelerated depreciation recovered	$ 2,500,000	$ 2,500,000