Regulatory Assets and Liabilities - Schedule of Regulatory Assets and Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Regulatory Assets [Line Items]
Total regulatory assets, net	$ 495,245	$ 423,279
Financing costs
Regulatory Assets [Line Items]
Regulatory assets	7,506	7,592
Postretirement costs
Regulatory Assets [Line Items]
Regulatory assets	14,915	15,411
Fair value of long-term debt
Regulatory Assets [Line Items]
Regulatory assets	117,703	119,553
Debt issuance costs
Regulatory Assets [Line Items]
Regulatory assets	5,170	5,254
CLECO POWER
Regulatory Assets [Line Items]
Regulatory assets	518,465	456,034
Regulatory liabilities	(168,514)	(180,565)
Total regulatory assets, net	349,951	275,469
CLECO POWER | Acquisition/ transaction costs
Regulatory Assets [Line Items]
Regulatory assets	1,992	2,019
CLECO POWER | Acquisition/ transaction costs | Coughlin transaction costs
Regulatory Assets [Line Items]
Regulatory assets	869	876
CLECO POWER | Accumulated deferred fuel
Regulatory Assets [Line Items]
Regulatory assets	69,832	28,194
CLECO POWER | AFUDC equity gross-up
Regulatory Assets [Line Items]
Regulatory assets	68,896	69,670
CLECO POWER | AMI deferred revenue requirement
Regulatory Assets [Line Items]
Regulatory assets	2,454	2,591
CLECO POWER | AROs
Regulatory Assets [Line Items]
Regulatory assets	6,345	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	17,052	17,051
CLECO POWER | Deferred storm restoration costs - Hurricane Zeta
Regulatory Assets [Line Items]
Regulatory assets	3,613	3,493
CLECO POWER | Deferred storm restoration costs - Winter Storms Uri & Viola
Regulatory Assets [Line Items]
Regulatory assets	1,938	0
CLECO POWER | Accelerated depreciation | Rodemacher Unit 2 closure costs
Regulatory Assets [Line Items]
Regulatory assets	2,722	1,333
CLECO POWER | Accelerated depreciation | Dolet Hills
Regulatory Assets [Line Items]
Regulatory assets	70,192	48,982
CLECO POWER | Emergency declarations
Regulatory Assets [Line Items]
Regulatory assets	131	270
CLECO POWER | Energy efficiency
Regulatory Assets [Line Items]
Regulatory assets	2,703	2,820
CLECO POWER | Financing costs
Regulatory Assets [Line Items]
Regulatory assets	7,091	7,184
CLECO POWER | Interest costs
Regulatory Assets [Line Items]
Regulatory assets	3,646	3,708
CLECO POWER | Non-service cost of postretirement benefits
Regulatory Assets [Line Items]
Regulatory assets	10,181	9,901
CLECO POWER | Other, net
Regulatory Assets [Line Items]
Regulatory assets	4,682	4,229
CLECO POWER | Postretirement costs
Regulatory Assets [Line Items]
Regulatory assets	160,674	165,437
CLECO POWER | Production operations and maintenance expenses
Regulatory Assets [Line Items]
Regulatory assets	3,361	4,058
CLECO POWER | St. Mary Clean Energy Center
Regulatory Assets [Line Items]
Regulatory assets	5,219	3,479
CLECO POWER | Training costs
Regulatory Assets [Line Items]
Regulatory assets	6,046	6,085
CLECO POWER | Tree trimming costs
Regulatory Assets [Line Items]
Regulatory assets	11,129	11,807
CLECO POWER | Hurricane Laura
Regulatory Assets [Line Items]
Regulatory assets	54,744	54,406
CLECO POWER | AFUDC
Regulatory Assets [Line Items]
Regulatory liabilities	(4,574)	(4,218)
CLECO POWER | Corporate franchise tax, net
Regulatory Assets [Line Items]
Regulatory liabilities	(1,133)	(763)
CLECO POWER | Deferred taxes, net
Regulatory Assets [Line Items]
Regulatory liabilities	$ (162,807)	$ (175,584)