Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ 467,647	$ 351,015	$ 1,173,792	$ 902,248
Revenue unrelated to contracts with customers
Other	20,324	7,241	56,238	32,029
Total revenue unrelated to contracts with customers	20,324	7,241	56,238	32,029
Operating revenue, net	487,971	358,256	1,230,030	934,277
Deferred lease amortization			6,137	0
Total retail revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	254,604	269,624	643,612	683,185
Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	142,265	139,162	327,340	338,357
Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	84,816	79,829	218,209	218,389
Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	36,830	43,380	109,545	121,445
Other retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	4,234	4,039	11,391	11,633
Surcharge
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	170	6,206	7,692	17,637
Electric customer credits
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(13,711)	(2,992)	(30,565)	(24,276)
Wholesale, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	181,564	61,204	445,629	157,995
Transmission
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	27,027	14,718	69,909	41,166
Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	4,452	5,469	14,642	19,902
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		4,900	11,400	13,400
Reserves for capital expenditures		200		2,400
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			11,700
CLECO POWER | SSR | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers		600	3,200	6,500
CLECO CAJUN
Revenue unrelated to contracts with customers
Deferred lease amortization	2,300		6,100
Operating Segments | CLECO POWER
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	342,982	353,658	877,535	910,158
Revenue unrelated to contracts with customers
Other	1,995	7,241	9,158	32,029
Total revenue unrelated to contracts with customers	1,995	7,241	9,158	32,029
Operating revenue, net	344,977	360,899	886,693	942,187
Operating Segments | CLECO POWER | Total retail revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	254,604	269,624	643,612	683,185
Operating Segments | CLECO POWER | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	142,265	139,162	327,340	338,357
Operating Segments | CLECO POWER | Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	84,816	79,829	218,209	218,389
Operating Segments | CLECO POWER | Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	36,830	43,380	109,545	121,445
Operating Segments | CLECO POWER | Other retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	4,234	4,039	11,391	11,633
Operating Segments | CLECO POWER | Surcharge
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	170	6,206	7,692	17,637
Operating Segments | CLECO POWER | Electric customer credits
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(13,711)	(2,992)	(30,565)	(24,276)
Operating Segments | CLECO POWER | Wholesale, net
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	69,558	63,624	179,633	165,255
Operating Segments | CLECO POWER | Transmission
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	14,034	14,718	38,679	41,166
Operating Segments | CLECO POWER | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	4,452	5,469	14,640	19,901
Operating Segments | CLECO POWER | Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	334	223	971	651
Operating Segments | CLECO CAJUN
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	129,892		309,912
Revenue unrelated to contracts with customers
Other	18,329		47,081
Total revenue unrelated to contracts with customers	18,329		47,081
Operating revenue, net	148,221		356,993
Lease revenue	16,000		40,900
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	114,426		273,256
Operating Segments | CLECO CAJUN | Transmission
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	15,435		36,625
Operating Segments | CLECO CAJUN | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0		0
Operating Segments | CLECO CAJUN | Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	31		31
OTHER
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	25,832	20,345	70,542	48,448
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	25,832	20,345	70,542	48,448
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)	(7,260)	(7,260)
OTHER | Transmission
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	2	1
OTHER | Affiliate
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	28,252	22,765	77,800	55,707
ELIMINATIONS
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(31,059)	(22,988)	(84,197)	(56,358)
Revenue unrelated to contracts with customers
Other	0	0	(1)	0
Total revenue unrelated to contracts with customers	0	0	(1)	0
Operating revenue, net	(31,059)	(22,988)	(84,198)	(56,358)
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	(2,442)	0	(5,395)	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	$ (28,617)	$ (22,988)	$ (78,802)	$ (56,358)