Pension Plan and Employee Benefits - Current and Non-Current Portions of the Other Benefits Liability (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Non-current	$ 315,249	$ 314,653
CLECO POWER
Defined Benefit Plan Disclosure [Line Items]
Non-current	231,810	230,825
Other Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Current	4,463	4,463
Non-current	51,727	51,868
Other Benefits Plan | CLECO POWER
Defined Benefit Plan Disclosure [Line Items]
Current	3,865	3,856
Non-current	$ 40,616	$ 40,734