Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ 375,454	$ 287,625	$ 706,145	$ 551,233
Revenue unrelated to contracts with customers
Other	22,419	11,636	35,915	24,788
Total revenue unrelated to contracts with customers	22,419	11,636	35,915	24,788
Operating revenue, net	397,873	299,261	742,060	576,021
Deferred lease amortization			3,835
Total retail revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	197,769	216,698	389,009	413,561
Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	97,927	107,805	185,075	199,195
Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	68,013	71,865	133,393	138,560
Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	34,845	40,679	72,715	78,065
Other retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3,476	3,793	7,157	7,594
Surcharge
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	2,201	6,193	7,522	11,431
Electric customer credits
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(8,693)	(13,637)	(16,853)	(21,284)
Wholesale, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	152,811	52,242	264,128	96,791
Transmission
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	21,575	11,943	42,883	26,448
Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3,299	6,742	10,125	14,433
Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
CLECO POWER | Other
Revenue unrelated to contracts with customers
Other miscellaneous fee revenue	2,500	4,100	6,900	8,600
Reserves for capital expenditures		300		2,200
CLECO POWER | Lost contribution to fixed cost
Revenue unrelated to contracts with customers
Other			(2,600)
CLECO POWER | Price Risk Derivative | Other
Revenue unrelated to contracts with customers
Other	4,900		9,800
CLECO POWER | SSR | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	800	2,600	3,200	5,800
CLECO CAJUN
Revenue unrelated to contracts with customers
Deferred lease amortization	2,400		3,800
Operating Segments | CLECO POWER
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	268,039	290,265	534,555	556,500
Revenue unrelated to contracts with customers
Other	4,933	11,636	7,162	24,788
Total revenue unrelated to contracts with customers	4,933	11,636	7,162	24,788
Operating revenue, net	272,972	301,901	541,717	581,288
Operating Segments | CLECO POWER | Total retail revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	197,769	216,698	389,009	413,561
Operating Segments | CLECO POWER | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	97,927	107,805	185,075	199,195
Operating Segments | CLECO POWER | Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	68,013	71,865	133,393	138,560
Operating Segments | CLECO POWER | Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	34,845	40,679	72,715	78,065
Operating Segments | CLECO POWER | Other retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3,476	3,793	7,157	7,594
Operating Segments | CLECO POWER | Surcharge
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	2,201	6,193	7,522	11,431
Operating Segments | CLECO POWER | Electric customer credits
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(8,693)	(13,637)	(16,853)	(21,284)
Operating Segments | CLECO POWER | Wholesale, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	54,529	54,662	110,075	101,631
Operating Segments | CLECO POWER | Transmission
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	12,067	11,943	24,645	26,448
Operating Segments | CLECO POWER | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3,337	6,742	10,189	14,432
Operating Segments | CLECO POWER | Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	337	220	637	428
Operating Segments | CLECO CAJUN
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	113,126		180,019
Revenue unrelated to contracts with customers
Other	17,486		28,753
Total revenue unrelated to contracts with customers	17,486		28,753
Operating revenue, net	130,612		208,772
Lease revenue	15,100		24,900
Operating Segments | CLECO CAJUN | Total retail revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0		0
Operating Segments | CLECO CAJUN | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0		0
Operating Segments | CLECO CAJUN | Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0		0
Operating Segments | CLECO CAJUN | Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0		0
Operating Segments | CLECO CAJUN | Other retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0		0
Operating Segments | CLECO CAJUN | Surcharge
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0		0
Operating Segments | CLECO CAJUN | Electric customer credits
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0		0
Operating Segments | CLECO CAJUN | Wholesale, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	100,702		158,893
Operating Segments | CLECO CAJUN | Transmission
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	12,462		21,190
Operating Segments | CLECO CAJUN | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(38)		(64)
Operating Segments | CLECO CAJUN | Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0		0
OTHER
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	20,592	14,853	44,709	28,103
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	20,592	14,853	44,709	28,103
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	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	2	0
OTHER | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	1
OTHER | Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	23,012	17,273	49,547	32,942
ELIMINATIONS
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(26,303)	(17,493)	(53,138)	(33,370)
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	(26,303)	(17,493)	(53,138)	(33,370)
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	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	(2,954)	0	(2,954)	0
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	$ (23,349)	$ (17,493)	$ (50,184)	$ (33,370)