Fair Value Accounting - Amount of Gain (Loss) Recognized in Income on Derivatives (Details) - DERIVATIVES NOT DESIGNATED AS HEDGING INSTRUMENTS - Price Risk Derivative - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Commodity-related contracts
Net gain (loss) recognized in income on derivatives	$ (4,579)	$ 10,878	$ (2,694)	$ 23,465
Accumulated deferred fuel
Commodity-related contracts
Unrealized gains (losses) associated with FTRs	(2,600)	2,400	(2,600)	2,400
Electric operations
Commodity-related contracts
Gain recognized in income on derivatives	5,204	12,067	10,413	25,166
Power purchased for utility customers
Commodity-related contracts
Loss recognized in income on derivatives	(7,013)	(1,189)	(10,337)	(1,701)
Fuel used for electric generation
Commodity-related contracts
Loss recognized in income on derivatives	(2,770)	0	(2,770)	0
CLECO POWER
Commodity-related contracts
Net gain (loss) recognized in income on derivatives	4,208	10,878	7,431	23,465
CLECO POWER | Accumulated deferred fuel
Commodity-related contracts
Unrealized gains (losses) associated with FTRs	(2,600)	2,400	(2,600)	2,400
CLECO POWER | Electric operations
Commodity-related contracts
Gain recognized in income on derivatives	5,197	12,067	10,403	25,166
CLECO POWER | Power purchased for utility customers
Commodity-related contracts
Loss recognized in income on derivatives	$ (989)	$ (1,189)	$ (2,972)	$ (1,701)