Regulation and Rates - Provision for Rate Refund (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Jul. 31, 2019
Regulation and Rates [Line Items]
Provision for rate refund	$ 8,933	$ 9,444
FRP
Regulation and Rates [Line Items]
Provision for rate refund	2,089	1,786
TCJA
Regulation and Rates [Line Items]
Provision for rate refund	2,057	2,057
Cleco Katrina/Rita storm recovery charges
Regulation and Rates [Line Items]
Provision for rate refund	1,609	1,617
FERC audit
Regulation and Rates [Line Items]
Provision for rate refund	951	1,912
Site-specific industrial customer
Regulation and Rates [Line Items]
Provision for rate refund	865	710
Transmission ROE
Regulation and Rates [Line Items]
Provision for rate refund	595	595
CLECO POWER
Regulation and Rates [Line Items]
Provision for rate refund	8,119	8,630	$ 79,200
CLECO POWER | FRP
Regulation and Rates [Line Items]
Provision for rate refund	2,089	1,786
CLECO POWER | TCJA
Regulation and Rates [Line Items]
Provision for rate refund	2,057	2,057
CLECO POWER | Cleco Katrina/Rita storm recovery charges
Regulation and Rates [Line Items]
Provision for rate refund	1,609	1,617
CLECO POWER | FERC audit
Regulation and Rates [Line Items]
Provision for rate refund	951	1,912
CLECO POWER | Site-specific industrial customer
Regulation and Rates [Line Items]
Provision for rate refund	865	710
CLECO POWER | Transmission ROE
Regulation and Rates [Line Items]
Provision for rate refund	$ 595	$ 595