Regulatory Assets and Liabilities - Schedule of Regulatory Assets and Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Jun. 16, 2021	Dec. 31, 2020
Regulatory Assets [Line Items]
Total regulatory assets, net	$ 572,751		$ 423,279
Financing costs
Regulatory Assets [Line Items]
Regulatory assets	7,419		7,592
Postretirement costs
Regulatory Assets [Line Items]
Regulatory assets	14,418		15,411
Fair value of long-term debt
Regulatory Assets [Line Items]
Regulatory assets	115,852		119,553
Debt issuance costs
Regulatory Assets [Line Items]
Regulatory assets	5,086		5,254
CLECO POWER
Regulatory Assets [Line Items]
Regulatory assets	583,746		456,034
Regulatory liabilities	(153,770)		(180,565)
Total regulatory assets, net	429,976		275,469
CLECO POWER | Acquisition/ transaction costs
Regulatory Assets [Line Items]
Regulatory assets	1,966		2,019
CLECO POWER | Acquisition/ transaction costs | Coughlin transaction costs
Regulatory Assets [Line Items]
Regulatory assets	861		876
CLECO POWER | Accumulated deferred fuel
Regulatory Assets [Line Items]
Regulatory assets	75,295		28,194
CLECO POWER | AFUDC equity gross-up
Regulatory Assets [Line Items]
Regulatory assets	68,122		69,670
CLECO POWER | Affordability study
Regulatory Assets [Line Items]
Regulatory assets	13,644	$ 13,600	0
CLECO POWER | AMI deferred revenue requirement
Regulatory Assets [Line Items]
Regulatory assets	2,318		2,591
CLECO POWER | AROs
Regulatory Assets [Line Items]
Regulatory assets	7,202		5,488
CLECO POWER | COVID-19 executive order
Regulatory Assets [Line Items]
Regulatory assets	2,953		2,953
CLECO POWER | Deferred storm restoration costs - Hurricane Delta
Regulatory Assets [Line Items]
Regulatory assets	17,802		17,051
CLECO POWER | Hurricane Laura
Regulatory Assets [Line Items]
Regulatory assets	56,412		54,406
CLECO POWER | Deferred storm restoration costs - Hurricane Zeta
Regulatory Assets [Line Items]
Regulatory assets	3,494		3,493
CLECO POWER | Deferred storm restoration costs - Winter Storms Uri & Viola
Regulatory Assets [Line Items]
Regulatory assets	1,980		0
CLECO POWER | Station closure costs | Dolet Hills
Regulatory Assets [Line Items]
Regulatory assets	91,479		48,982
CLECO POWER | Mine closure costs | Dolet Hills
Regulatory Assets [Line Items]
Regulatory assets	13,910		0
CLECO POWER | Emergency declarations
Regulatory Assets [Line Items]
Regulatory assets	0		270
CLECO POWER | Energy efficiency
Regulatory Assets [Line Items]
Regulatory assets	2,350		2,820
CLECO POWER | Financing costs
Regulatory Assets [Line Items]
Regulatory assets	7,011		7,184
CLECO POWER | Interest costs
Regulatory Assets [Line Items]
Regulatory assets	3,583		3,708
CLECO POWER | Madison Unit 3 property taxes
Regulatory Assets [Line Items]
Regulatory assets	4,181		0
CLECO POWER | Non-service cost of postretirement benefits
Regulatory Assets [Line Items]
Regulatory assets	10,881		9,901
CLECO POWER | Other
Regulatory Assets [Line Items]
Regulatory assets	13,040		4,229
CLECO POWER | Postretirement costs
Regulatory Assets [Line Items]
Regulatory assets	155,067		165,437
CLECO POWER | Production operations and maintenance expenses
Regulatory Assets [Line Items]
Regulatory assets	2,664		4,058
CLECO POWER | Rodemacher Unit 2 deferred costs | Rodemacher Unit 2 deferred costs
Regulatory Assets [Line Items]
Regulatory assets	4,115		1,333
CLECO POWER | St. Mary Clean Energy Center
Regulatory Assets [Line Items]
Regulatory assets	6,959		3,479
CLECO POWER | Training costs
Regulatory Assets [Line Items]
Regulatory assets	6,007		6,085
CLECO POWER | Tree trimming costs
Regulatory Assets [Line Items]
Regulatory assets	10,450		11,807
CLECO POWER | AFUDC
Regulatory Assets [Line Items]
Regulatory liabilities	(5,359)		(4,218)
CLECO POWER | Corporate franchise tax, net
Regulatory Assets [Line Items]
Regulatory liabilities	0		(763)
CLECO POWER | Deferred taxes, net
Regulatory Assets [Line Items]
Regulatory liabilities	$ (148,411)		$ (175,584)