Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ 338,399	$ 375,454	$ 666,688	$ 706,145
Revenue unrelated to contracts with customers
Other	19,359	22,419	38,642	35,915
Total revenue unrelated to contracts with customers	19,359	22,419	38,642	35,915
Operating revenue, net	357,758	397,873	705,330	742,060
Electric customer credits	9,100	9,960	17,593	18,120
Deferred lease amortization			4,603	3,835
Total retail revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	183,674	197,769	356,129	389,009
Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	97,973	97,927	179,544	185,075
Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	61,575	68,013	122,685	133,393
Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	29,208	34,845	61,418	72,715
Other retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3,341	3,476	6,802	7,157
Surcharge
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers		2,201	2,443	7,522
Electric customer credits
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(8,423)	(8,693)	(16,763)	(16,853)
Wholesale, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	128,007	152,811	256,963	264,128
Transmission
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	23,117	21,575	46,300	42,883
Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3,601	3,299	7,296	10,125
Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
CLECO POWER
Revenue unrelated to contracts with customers
Deferred lease amortization		2,400	4,600	3,800
CLECO POWER | Lost contribution to fixed cost
Revenue unrelated to contracts with customers
Other				(2,600)
CLECO POWER | Price Risk Derivative
Revenue unrelated to contracts with customers
Other	1,900	4,900	3,300	9,800
CLECO POWER | SSR | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers		800		3,200
CLECO CAJUN
Revenue unrelated to contracts with customers
Lease revenue		15,100	30,800	24,900
Deferred lease amortization	2,300
OPERATING SEGMENTS
Revenue unrelated to contracts with customers
Operating revenue, net	363,099	403,584	716,175	750,489
Electric customer credits	9,100	9,960	17,593	18,120
OPERATING SEGMENTS | CLECO POWER
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	245,834	268,039	477,388	534,555
Revenue unrelated to contracts with customers
Other	1,853	4,933	3,259	7,162
Total revenue unrelated to contracts with customers	1,853	4,933	3,259	7,162
Operating revenue, net	247,687	272,972	480,647	541,717
Electric customer credits	9,100	8,693	17,440	16,853
OPERATING SEGMENTS | CLECO POWER | Total retail revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	183,674	197,769	356,129	389,009
OPERATING SEGMENTS | CLECO POWER | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	97,973	97,927	179,544	185,075
OPERATING SEGMENTS | CLECO POWER | Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	61,575	68,013	122,685	133,393
OPERATING SEGMENTS | CLECO POWER | Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	29,208	34,845	61,418	72,715
OPERATING SEGMENTS | CLECO POWER | Other retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3,341	3,476	6,802	7,157
OPERATING SEGMENTS | CLECO POWER | Surcharge
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers		2,201	2,443	7,522
OPERATING SEGMENTS | CLECO POWER | Electric customer credits
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(8,423)	(8,693)	(16,763)	(16,853)
OPERATING SEGMENTS | CLECO POWER | Wholesale, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	45,694	54,529	87,923	110,075
OPERATING SEGMENTS | CLECO POWER | Transmission
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	11,625	12,067	23,694	24,645
Revenue unrelated to contracts with customers
Electric customer credits	700		700
OPERATING SEGMENTS | CLECO POWER | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3,601	3,337	7,296	10,189
Revenue unrelated to contracts with customers
Other miscellaneous fee revenue		2,500		6,900
OPERATING SEGMENTS | CLECO POWER | Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1,240	337	2,346	637
OPERATING SEGMENTS | CLECO CAJUN
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	97,907	113,126	200,146	180,019
Revenue unrelated to contracts with customers
Other	17,505	17,486	35,382	28,753
Total revenue unrelated to contracts with customers	17,505	17,486	35,382	28,753
Operating revenue, net	115,412	130,612	235,528	208,772
Electric customer credits	0	1,267	153	1,267
Lease revenue	15,200
OPERATING SEGMENTS | CLECO CAJUN | Total retail revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
OPERATING SEGMENTS | CLECO CAJUN | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
OPERATING SEGMENTS | CLECO CAJUN | Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
OPERATING SEGMENTS | CLECO CAJUN | Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
OPERATING SEGMENTS | CLECO CAJUN | Other retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
OPERATING SEGMENTS | CLECO CAJUN | Surcharge
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers		0	0	0
OPERATING SEGMENTS | CLECO CAJUN | Electric customer credits
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
OPERATING SEGMENTS | CLECO CAJUN | Wholesale, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	84,733	100,702	173,880	158,893
OPERATING SEGMENTS | CLECO CAJUN | Transmission
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	13,131	12,462	26,062	21,190
Revenue unrelated to contracts with customers
Electric customer credits			200
OPERATING SEGMENTS | CLECO CAJUN | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	(38)	0	(64)
OPERATING SEGMENTS | CLECO CAJUN | Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	43	0	204	0
OTHER
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	26,718	20,592	53,575	44,709
Revenue unrelated to contracts with customers
Other	1	0	1	0
Total revenue unrelated to contracts with customers	1	0	1	0
Operating revenue, net	26,719	20,592	53,576	44,709
Electric customer credits	0	0	0	0
OTHER | Total retail revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
OTHER | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
OTHER | Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
OTHER | Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
OTHER | Other retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
OTHER | Surcharge
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers		0	0	0
OTHER | Electric customer credits
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
OTHER | Wholesale, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(2,420)	(2,420)	(4,840)	(4,840)
OTHER | Transmission
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	2
OTHER | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
OTHER | Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	29,138	23,012	58,415	49,547
ELIMINATIONS
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(32,060)	(26,303)	(64,421)	(53,138)
Revenue unrelated to contracts with customers
Other	0	0	0	0
Total revenue unrelated to contracts with customers	0	0	0	0
Operating revenue, net	(32,060)	(26,303)	(64,421)	(53,138)
Electric customer credits	0	0	0	0
ELIMINATIONS | Total retail revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
ELIMINATIONS | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
ELIMINATIONS | Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
ELIMINATIONS | Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
ELIMINATIONS | Other retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
ELIMINATIONS | Surcharge
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers		0	0	0
ELIMINATIONS | Electric customer credits
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
ELIMINATIONS | Wholesale, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
ELIMINATIONS | Transmission
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(1,639)	(2,954)	(3,456)	(2,954)
ELIMINATIONS | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
ELIMINATIONS | Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ (30,421)	$ (23,349)	$ (60,965)	$ (50,184)