Schedule I - Condensed Financial Information Of Registrant (Unconsolidated Statements Of Common Shareholders' Equity (Deficit)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Condensed Financial Statements, Captions [Line Items]
Other Comprehensive Income (Loss), Net of Tax	$ 7,025	$ 51,676	$ 14,013
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	1,090,518
Net income / (loss)	83,120	93,117	115,969
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	90,145	144,793	129,982
Distributions to AES	(104,287)	(101,986)	(131,476)
Equity contributions from shareholders	0	253,000	275,000
Other	92	111	106
Ending Balance	1,129,722	1,090,518
Contributions from shareholders		253,000	275,000
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Other Comprehensive Income (Loss), Net of Tax	7,025	51,676	14,013
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	1,090,518	794,600	520,988
Net income / (loss)	83,120	93,117	115,969
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	90,145	144,793	129,982
Distributions to AES	104,287	101,986	131,476
Equity contributions from shareholders	0	253,000	275,000
Other	92	111	106
Ending Balance	1,076,468	1,090,518	794,600
Net cash used in investing activities	0	(253,000)	(275,000)
Contributions from shareholders		253,000
Subsidiaries [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	1,943,710
Net income / (loss)	116,190	126,466	147,030
Other	92	114	107
Ending Balance	1,973,046	1,943,710
Contributions from shareholders	0	253,000	275,000
Paid In Capital [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Return of Capital	(46,500)	(33,300)	(15,500)
Equity contributions from shareholders
Other	92	111	106
Contributions from shareholders		253,000	275,000
Paid In Capital [Member] | Parent Company [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	1,068,357	848,565	588,966
Return of Capital	(46,457)	(33,319)	(15,507)
Other	92	111	106
Ending Balance	1,021,992	1,068,357	848,565
Contributions from shareholders		253,000
Paid In Capital [Member] | Subsidiaries [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other	92	114	107
Contributions from shareholders	0	253,000	275,000
AOCI Attributable to Parent [Member]
Condensed Financial Statements, Captions [Line Items]
Other Comprehensive Income (Loss), Net of Tax	7,025	51,676	14,013
AOCI Attributable to Parent [Member] | Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Other Comprehensive Income (Loss), Net of Tax	7,025	51,676	14,013
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	22,269	(29,407)	(43,420)
Ending Balance	29,294	22,269	(29,407)
Accumulated Deficit [Member]
Condensed Financial Statements, Captions [Line Items]
Other Comprehensive Income (Loss), Net of Tax	0	0	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income / (loss)	83,120	96,626	119,182
Distributions to AES	(57,830)	(68,667)	(115,969)
Accumulated Deficit [Member] | Parent Company [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	(108)	(24,558)	(24,558)
Net income / (loss)	83,120	93,117	115,969
Distributions to AES	57,830	68,667	115,969
Ending Balance	$ 25,182	$ (108)	$ (24,558)