Regulatory Assets and Liabilities, Summary of Regulatory Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Feb. 01, 2016
Regulatory Assets and Liabilities [Line Items]
Total regulatory assets, net	$ 330,582	$ 739,683
2017 Tax Reform [Member]
Regulatory Assets and Liabilities [Line Items]
Regulatory liabilities	(348,600)
Postretirement costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	21,375	23,362
Financing costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	8,623	8,966
Fair value of long-term debt
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	147,145	155,776
Debt issuance cost
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	6,665	7,606
Cleco Power [Member]
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	273,220	285,737
Total regulatory assets, net	146,774	543,973
Cleco Power [Member] | 2017 Tax Reform [Member]
Regulatory Assets and Liabilities [Line Items]
Regulatory liabilities	(348,590)	0
Cleco Power [Member] | Total investment tax credit [Member]
Regulatory Assets and Liabilities [Line Items]
Regulatory liabilities	(372)	(1,002)
Cleco Power [Member] | Total federal regulatory asset - income taxes [Member]
Regulatory Assets and Liabilities [Line Items]
Regulatory liabilities	(64,205)	(635)
Cleco Power [Member] | Total state regulatory asset — income taxes
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	142,788	112,751
Cleco Power [Member] | AFUDC
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	129,953	126,335
Cleco Power [Member] | Total regulatory assets — deferred taxes, net
Regulatory Assets and Liabilities [Line Items]
Regulatory assets		237,449
Regulatory liabilities	(140,426)
Cleco Power [Member] | Mining costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	$ 3,823	6,372
Remaining Recovery Period of Regulatory Assets	2 years 6 months
Cleco Power [Member] | Interest costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	$ 4,499	4,860
Cleco Power [Member] | AROs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	2,762	2,096
Cleco Power [Member] | Postretirement costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	142,764	145,268
Cleco Power [Member] | Tree trimming costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	7,193	5,549
Cleco Power [Member] | Training costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	$ 6,552	6,708
Remaining Recovery Period of Regulatory Assets	43 years
Cleco Power [Member] | Surcredits, net
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	$ 2,173	5,876
Cleco Power [Member] | AMI deferred revenue requirement
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	$ 4,227	4,772
Remaining Recovery Period of Regulatory Assets	9 years
Cleco Power [Member] | Emergency declarations
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	$ 4,131	0
Cleco Power [Member] | Production operations and maintenance expenses
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	8,625	13,999
Cleco Power [Member] | AFUDC equity gross-up
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	71,205	70,423
Cleco Power [Member] | Acquisition costs or Transaction costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	$ 2,336	2,442
Remaining Recovery Period of Regulatory Assets	23 years
Cleco Power [Member] | Acquisition costs or Transaction costs | Natural Gas Processing Plant [Member]
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	$ 968	999
Remaining Recovery Period of Regulatory Assets	32 years 6 months
Cleco Power [Member] | Financing costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	$ 8,293	8,663
Cleco Power [Member] | Biomass costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	$ 0	18
Remaining Recovery Period of Regulatory Assets	6 months
Cleco Power [Member] | MISO Integration Costs
Regulatory Assets and Liabilities [Line Items]
Remaining Recovery Period of Regulatory Assets	1 year 6 months
Cleco Power [Member] | MISO Integration Costs | Natural Gas Processing Plant [Member]
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	$ 468	1,404
Cleco Power [Member] | Corporate franchise tax
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	153	1,308
Cleco Power [Member] | MATS costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	$ 2,564	4,270	$ 7,100
Remaining Recovery Period of Regulatory Assets	1 year 6 months
Cleco Power [Member] | Other
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	$ 484	710
Cleco Power [Member] | Accumulated deferred fuel
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	$ 13,980	$ 20,787