Condensed Consolidated Statements Of Common Shareholder's Equity (Deficit) And Noncontrolling Interest (USD $) In Thousands, unless otherwise specified	Paid In Capital [Member]	Accumulated Deficit [Member]	Cumulative Preferred Stock Of Subsidiary [Member]	Total
Beginning Balance at Dec. 31, 2011	$ 11,367	$ (17,213)	$ 59,784	$ (5,846)
Comprehensive Income attributable to common stock:
Net income applicable to common stock		53,451		53,451
Distributions to AES		(44,600)		(44,600)
Contributions from AES	365			365
Balance at Sep. 30, 2012	11,732	(8,362)	59,784	3,370
Beginning Balance at Dec. 31, 2012	11,811	(15,030)	59,784	(3,219)
Comprehensive Income attributable to common stock:
Net income applicable to common stock		56,175		56,175
Distributions to AES		(43,650)		(43,650)
Contributions from AES	49,604			49,604
Balance at Sep. 30, 2013	$ 61,415	$ (2,505)	$ 59,784	$ 58,910