Pension Plan and Employee Benefits - Current and Non-Current Portions of the Other Benefits Liability (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Non-current	$ 320,504	$ 314,653
CLECO POWER
Defined Benefit Plan Disclosure [Line Items]
Non-current	237,818	230,825
Other Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Current	4,463	4,463
Non-current	51,306	51,868
Other Benefits Plan | CLECO POWER
Defined Benefit Plan Disclosure [Line Items]
Current	3,865	3,865
Non-current	$ 40,261	$ 40,734