Fair Value Accounting - Fair Value of Derivative Instruments as Recorded in Condensed Consolidated Balance Sheets (Details) - DERIVATIVES NOT DESIGNATED AS HEDGING INSTRUMENTS - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Commodity-related contracts
Commodity-related contracts, net	$ 22,670	$ 606
Commodity-related contracts | CLECO POWER
Commodity-related contracts
Commodity-related contracts, net	5,412	5,725
Commodity-related contracts | Energy risk management assets
Commodity-related contracts
Derivative asset	7,907	6,822
Commodity-related contracts | Energy risk management assets | CLECO POWER
Commodity-related contracts
Derivative asset	7,177	6,311
Commodity-related contracts | Energy risk management liabilities
Commodity-related contracts
Derivative liability	(2,580)	(1,044)
Commodity-related contracts | Energy risk management liabilities | CLECO POWER
Commodity-related contracts
Derivative liability	(1,765)	(586)
Other commodity derivatives | Energy risk management assets
Commodity-related contracts
Derivative asset	12,067	201
Other commodity derivatives | Energy risk management liabilities
Commodity-related contracts
Derivative liability	0	(3,069)
Other commodity derivatives | Other deferred charges
Commodity-related contracts
Derivative asset	5,276	0
Other commodity derivatives | Other deferred credits
Commodity-related contracts
Derivative liability	$ 0	$ (2,304)