Income Taxes - Current and Deferred Income Tax Expense (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Apr. 12, 2016	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SUCCESSOR
Components of Income Tax Expense [Line Items]
Current federal income tax expense (benefit)		$ (1,062)	$ 15,304	$ 46,520
Deferred federal income tax expense (benefit)		(16,715)	5,863	(47,329)
Amortization of accumulated deferred investment tax credits		(371)	(236)	(662)
Total federal income tax expense (benefit)		(18,148)	20,931	(1,471)
Current state income tax expense (benefit)		(337)	7,771	3,187
Deferred state income tax expense (benefit)		(4,337)	680	5,363
Total state income tax expense (benefit)		(4,674)	8,451	8,550
Total tax expense (benefit)		(22,822)	29,382	7,079
Items charged or credited directly to member’s/shareholders’ equity
Total tax expense (benefit) from items charged directly to member’s/shareholders’ equity		938	1,868	(2,764)
Total federal and state income tax expense (benefit)		(21,884)	31,250	4,315
SUCCESSOR | Federal deferred
Items charged or credited directly to member’s/shareholders’ equity
Total tax expense (benefit) from items charged directly to member’s/shareholders’ equity		808	1,408	(2,380)
SUCCESSOR | State deferred
Items charged or credited directly to member’s/shareholders’ equity
Total tax expense (benefit) from items charged directly to member’s/shareholders’ equity		$ 130	460	(384)
PREDECESSOR
Components of Income Tax Expense [Line Items]
Current federal income tax expense (benefit)	$ 1,373
Deferred federal income tax expense (benefit)	5,297
Amortization of accumulated deferred investment tax credits	(124)
Total federal income tax expense (benefit)	6,546
Current state income tax expense (benefit)	0
Deferred state income tax expense (benefit)	(3,078)
Total state income tax expense (benefit)	(3,078)
Total tax expense (benefit)	3,468
Items charged or credited directly to member’s/shareholders’ equity
Total tax expense (benefit) from items charged directly to member’s/shareholders’ equity	404
Total federal and state income tax expense (benefit)	3,872
PREDECESSOR | Federal deferred
Items charged or credited directly to member’s/shareholders’ equity
Total tax expense (benefit) from items charged directly to member’s/shareholders’ equity	348
PREDECESSOR | State deferred
Items charged or credited directly to member’s/shareholders’ equity
Total tax expense (benefit) from items charged directly to member’s/shareholders’ equity	$ 56
CLECO POWER
Components of Income Tax Expense [Line Items]
Current federal income tax expense (benefit)			44,411	87,433	$ (1,211)
Deferred federal income tax expense (benefit)			(9,033)	(29,190)	22,647
Amortization of accumulated deferred investment tax credits			(236)	(662)	(494)
Total federal income tax expense (benefit)			35,142	57,581	20,942
Current state income tax expense (benefit)			23,293	14,751	(418)
Deferred state income tax expense (benefit)			(2,511)	(5,001)	(2,155)
Total state income tax expense (benefit)			20,782	9,750	(2,573)
Total tax expense (benefit)			55,924	67,331	18,369
Items charged or credited directly to member’s/shareholders’ equity
Total tax expense (benefit) from items charged directly to member’s/shareholders’ equity			1,058	(164)	2,295
Total federal and state income tax expense (benefit)			56,982	67,167	20,664
CLECO POWER | Federal deferred
Items charged or credited directly to member’s/shareholders’ equity
Total tax expense (benefit) from items charged directly to member’s/shareholders’ equity			797	(141)	1,976
CLECO POWER | State deferred
Items charged or credited directly to member’s/shareholders’ equity
Total tax expense (benefit) from items charged directly to member’s/shareholders’ equity			$ 261	$ (23)	$ 319