Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ 359,657	$ 338,399	$ 729,774	$ 666,688
Revenue unrelated to contracts with customers
Other	19,092	19,359	43,969	38,642
Total revenue unrelated to contracts with customers	19,092	19,359	43,969	38,642
Operating revenue, net	378,749	357,758	773,743	705,330
Electric customer credits	18,517	9,100	39,494	17,593
Deferred lease amortization			4,603	4,603
Total retail revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	195,914	183,674	373,281	356,129
Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	105,315	97,973	200,396	179,544
Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	68,392	61,575	131,418	122,685
Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	37,385	29,208	74,051	61,418
Other retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3,876	3,341	7,446	6,802
Surcharge
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers				2,443
Electric customer credits
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(19,054)	(8,423)	(40,030)	(16,763)
Wholesale, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	135,203	128,007	296,012	256,963
Transmission, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	25,291	23,117	52,590	46,300
Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3,249	3,601	7,891	7,296
Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
CLECO CAJUN
Revenue unrelated to contracts with customers
Lease revenue		15,200	30,500	30,800
Deferred lease amortization	2,300	2,300	4,600	4,600
OPERATING SEGMENTS
Revenue unrelated to contracts with customers
Operating revenue, net	383,985	363,099	784,995	716,175
Electric customer credits	18,518	9,100	39,494	17,593
OPERATING SEGMENTS | CLECO POWER
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	259,916	245,834	519,284	477,388
Revenue unrelated to contracts with customers
Other	1,763	1,853	8,859	3,259
Total revenue unrelated to contracts with customers	1,763	1,853	8,859	3,259
Operating revenue, net	261,679	247,687	528,143	480,647
Electric customer credits	18,762	9,100	39,738	17,440
OPERATING SEGMENTS | CLECO POWER | Total retail revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	195,914	183,674	373,281	356,129
OPERATING SEGMENTS | CLECO POWER | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	105,315	97,973	200,396	179,544
OPERATING SEGMENTS | CLECO POWER | Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	68,392	61,575	131,418	122,685
OPERATING SEGMENTS | CLECO POWER | Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	37,385	29,208	74,051	61,418
OPERATING SEGMENTS | CLECO POWER | Other retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3,876	3,341	7,446	6,802
OPERATING SEGMENTS | CLECO POWER | Surcharge
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers				2,443
OPERATING SEGMENTS | CLECO POWER | Electric customer credits
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(19,054)	(8,423)	(40,030)	(16,763)
OPERATING SEGMENTS | CLECO POWER | Wholesale, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	46,216	45,694	107,938	87,923
OPERATING SEGMENTS | CLECO POWER | Transmission, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	13,313	11,625	27,295	23,694
Revenue unrelated to contracts with customers
Electric customer credits	300	700	300	700
OPERATING SEGMENTS | CLECO POWER | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3,249	3,601	7,891	7,296
OPERATING SEGMENTS | CLECO POWER | Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1,224	1,240	2,879	2,346
OPERATING SEGMENTS | CLECO CAJUN
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	104,980	97,907	221,744	200,146
Revenue unrelated to contracts with customers
Other	17,326	17,505	35,108	35,382
Total revenue unrelated to contracts with customers	17,326	17,505	35,108	35,382
Operating revenue, net	122,306	115,412	256,852	235,528
Electric customer credits	(244)	0	(244)	153
Lease revenue	15,000
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
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	91,407	84,733	192,914	173,880
OPERATING SEGMENTS | CLECO CAJUN | Transmission, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	13,573	13,131	28,830	26,062
Revenue unrelated to contracts with customers
Electric customer credits	200		200	200
OPERATING SEGMENTS | CLECO CAJUN | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
OPERATING SEGMENTS | CLECO CAJUN | Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	43	0	204
OTHER
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	23,700	26,718	48,436	53,575
Revenue unrelated to contracts with customers
Other	1	1	2	1
Total revenue unrelated to contracts with customers	1	1	2	1
Operating revenue, net	23,701	26,719	48,438	53,576
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
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, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
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	26,120	29,138	53,276	58,415
ELIMINATIONS
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(28,939)	(32,060)	(59,690)	(64,421)
Revenue unrelated to contracts with customers
Other	2	0	0	0
Total revenue unrelated to contracts with customers	2	0	0	0
Operating revenue, net	(28,937)	(32,060)	(59,690)	(64,421)
Electric customer credits	(1)	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
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
ELIMINATIONS | Transmission, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(1,595)	(1,639)	(3,535)	(3,456)
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	$ (27,344)	$ (30,421)	$ (56,155)	$ (60,965)