Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ 330,690	$ 263,608
Electric customer credits	(8,160)	(7,647)
Revenue unrelated to contracts with customers
Other	13,496	13,152
Total revenue unrelated to contracts with customers	13,496	13,152
Operating revenue, net	344,186	276,760
Deferred lease amortization	1,440
Total retail revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	191,240	196,863
Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	87,148	91,390
Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	65,380	66,695
Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	37,870	37,386
Other retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3,681	3,801
Surcharge
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	5,321	5,238
Wholesale, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	111,317	41,410
Transmission
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	21,306	17,644
Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	6,827	7,691
Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
CLECO POWER | Other
Revenue unrelated to contracts with customers
Other miscellaneous fee revenue	4,400	1,900
CLECO POWER | Lost contribution to fixed cost
Revenue unrelated to contracts with customers
Other	(2,600)
CLECO POWER | SSR | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	2,400	3,200
CLECO POWER | Price Risk Derivative | Other
Revenue unrelated to contracts with customers
Other	4,800
CLECO CAJUN
Revenue unrelated to contracts with customers
Deferred lease amortization	1,400
Operating Segments | CLECO POWER
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	266,516	266,235
Electric customer credits	(8,160)	(7,647)
Revenue unrelated to contracts with customers
Other	2,229	13,152
Total revenue unrelated to contracts with customers	2,229	13,152
Operating revenue, net	268,745	279,387
Operating Segments | CLECO POWER | Total retail revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	191,240	196,863
Operating Segments | CLECO POWER | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	87,148	91,390
Operating Segments | CLECO POWER | Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	65,380	66,695
Operating Segments | CLECO POWER | Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	37,870	37,386
Operating Segments | CLECO POWER | Other retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3,681	3,801
Operating Segments | CLECO POWER | Surcharge
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	5,321	5,238
Operating Segments | CLECO POWER | Wholesale, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	55,546	43,830
Operating Segments | CLECO POWER | Transmission
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	12,579	17,644
Operating Segments | CLECO POWER | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	6,851	7,690
Operating Segments | CLECO POWER | Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	300	208
Operating Segments | CLECO CAJUN
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	66,892
Electric customer credits	0
Revenue unrelated to contracts with customers
Other	11,267
Total revenue unrelated to contracts with customers	11,267
Operating revenue, net	78,159
Lease revenue	9,800
Operating Segments | CLECO CAJUN | Total retail revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0
Operating Segments | CLECO CAJUN | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0
Operating Segments | CLECO CAJUN | Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0
Operating Segments | CLECO CAJUN | Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0
Operating Segments | CLECO CAJUN | Other retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0
Operating Segments | CLECO CAJUN | Surcharge
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0
Operating Segments | CLECO CAJUN | Wholesale, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	58,191
Operating Segments | CLECO CAJUN | Transmission
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	8,727
Operating Segments | CLECO CAJUN | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(26)
Operating Segments | CLECO CAJUN | Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0
OTHER
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	24,117	13,250
Electric customer credits	0	0
Revenue unrelated to contracts with customers
Other	0	0
Total revenue unrelated to contracts with customers	0	0
Operating revenue, net	24,117	13,250
OTHER | Total retail revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
OTHER | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
OTHER | Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
OTHER | Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
OTHER | Other retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
OTHER | Surcharge
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
OTHER | Wholesale, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(2,420)	(2,420)
OTHER | Transmission
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
OTHER | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	2	1
OTHER | Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	26,535	15,669
ELIMINATIONS
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(26,835)	(15,877)
Electric customer credits	0	0
Revenue unrelated to contracts with customers
Other	0	0
Total revenue unrelated to contracts with customers	0	0
Operating revenue, net	(26,835)	(15,877)
ELIMINATIONS | Total retail revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
ELIMINATIONS | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
ELIMINATIONS | Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
ELIMINATIONS | Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
ELIMINATIONS | Other retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
ELIMINATIONS | Surcharge
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
ELIMINATIONS | Wholesale, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
ELIMINATIONS | Transmission
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
ELIMINATIONS | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
ELIMINATIONS | Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ (26,835)	$ (15,877)