Regulatory Assets and Liabilities, Additional Disclosures (Details) $ in Thousands	1 Months Ended				12 Months Ended
	Dec. 31, 2017 USD ($)	Nov. 30, 2017 USD ($)	Dec. 31, 2016 USD ($)	May 31, 2013 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2011 USD ($) Locks	Oct. 31, 2016 USD ($)	Feb. 01, 2016 USD ($)	Apr. 30, 2013 USD ($)	Feb. 28, 2011 USD ($)
Regulatory Assets and Liabilities [Line Items]
Derecognized fair value adjustment and debt issuance costs related to debt redemption					$ 700
Financing costs
Regulatory Assets and Liabilities [Line Items]
Regulatory Assets	$ 8,623		$ 8,966		8,623	$ 8,966
Postretirement costs
Regulatory Assets and Liabilities [Line Items]
Regulatory Assets	21,375		23,362		21,375	23,362
Cleco Power [Member]
Regulatory Assets and Liabilities [Line Items]
Regulatory Assets	273,220		285,737		273,220	285,737
Increase (Decrease) in deferred fuel costs					$ (11,909)	7,215	$ (9,899)
Cleco Power [Member] | Treasury Lock [Member]
Regulatory Assets and Liabilities [Line Items]
Number of Interest Rate Derivatives Held | Locks								2
Gain (Loss) on Sale of Derivatives								$ 26,800
Cleco Power [Member] | Interest Rate Swap [Member]
Regulatory Assets and Liabilities [Line Items]
Gain (Loss) on Sale of Derivatives				$ 3,300
Cleco Power [Member] | Mining costs
Regulatory Assets and Liabilities [Line Items]
Regulatory Noncurrent Asset, Amortization Period					11 years 6 months
Regulatory Assets	3,823		6,372		$ 3,823	6,372
Cleco Power [Member] | Financing costs
Regulatory Assets and Liabilities [Line Items]
Regulatory Assets	8,293		8,663		$ 8,293	8,663
Cleco Power [Member] | Financing costs | Treasury Lock [Member]
Regulatory Assets and Liabilities [Line Items]
Regulatory Assets								$ 7,400
Cleco Power [Member] | Financing costs | Interest Rate Swap [Member]
Regulatory Assets and Liabilities [Line Items]
Regulatory Assets				$ 2,900
Cleco Power [Member] | Postretirement costs
Regulatory Assets and Liabilities [Line Items]
Regulatory Noncurrent Asset, Amortization Period					10 years
Regulatory Assets	142,764		145,268		$ 142,764	145,268
Cleco Power [Member] | Tree trimming costs
Regulatory Assets and Liabilities [Line Items]
Regulatory Noncurrent Asset, Amortization Period					3 years 6 months
Anticipated removal costs					$ 20,800
Maximum amount of costs approved to defer									$ 10,900
Regulatory Assets	7,193		5,549		7,193	5,549
Anticipated removal costs to be expensed					4,000
Anticipated amount of removal costs to be deferred and recovered					$ 5,900
Cleco Power [Member] | Training costs
Regulatory Assets and Liabilities [Line Items]
Regulatory Noncurrent Asset, Amortization Period					50 years
Regulatory Assets	6,552		6,708		$ 6,552	6,708
Cleco Power [Member] | Surcredits, net
Regulatory Assets and Liabilities [Line Items]
Regulatory Noncurrent Asset, Amortization Period					4 years
Withdrawal from restricted storm reserve		$ 4,000
Regulatory Assets	2,173		5,876		$ 2,173	5,876
Cleco Power [Member] | AMI deferred revenue requirement
Regulatory Assets and Liabilities [Line Items]
Regulatory Noncurrent Asset, Amortization Period					11 years
Regulatory Assets	4,227		4,772		$ 4,227	4,772
Cleco Power [Member] | AMI deferred revenue requirement | Maximum [Member]
Regulatory Assets and Liabilities [Line Items]
Regulatory Assets												$ 20,000
Cleco Power [Member] | Emergency declarations
Regulatory Assets and Liabilities [Line Items]
Regulatory Noncurrent Asset, Amortization Period					3 years
Regulatory Assets	4,131		0		$ 4,131	0
Cleco Power [Member] | Production O&M Expenses
Regulatory Assets and Liabilities [Line Items]
Regulatory Noncurrent Asset, Amortization Period					3 years
Authorized Production Operations and Maintenance Deferral, Threshold	45,000				$ 45,000
Increase (Decrease) in Other Regulatory Assets	400		7,300
Cleco Power [Member] | Production O&M Expenses | Maximum [Member]
Regulatory Assets and Liabilities [Line Items]
Regulatory Assets	23,000				$ 23,000
Cleco Power [Member] | Acquisition costs or Transaction costs
Regulatory Assets and Liabilities [Line Items]
Regulatory Noncurrent Asset, Amortization Period					30 years
Regulatory Assets	2,336		2,442		$ 2,336	2,442
Cleco Power [Member] | Acquisition costs or Transaction costs | Natural Gas Processing Plant [Member]
Regulatory Assets and Liabilities [Line Items]
Regulatory Noncurrent Asset, Amortization Period					35 years
Regulatory Assets	968		999		$ 968	999
Cleco Power [Member] | Biomass Costs
Regulatory Assets and Liabilities [Line Items]
Regulatory Noncurrent Asset, Amortization Period					5 years
Cleco Power [Member] | MISO Integration Costs
Regulatory Assets and Liabilities [Line Items]
Regulatory Noncurrent Asset, Amortization Period					4 years
Cleco Power [Member] | MISO Integration Costs | Natural Gas Processing Plant [Member]
Regulatory Assets and Liabilities [Line Items]
Regulatory Assets	468		1,404		$ 468	1,404
Cleco Power [Member] | Corporate franchise tax
Regulatory Assets and Liabilities [Line Items]
Regulatory Noncurrent Asset, Amortization Period					12 months
Regulatory Assets	153		1,308		$ 153	1,308
Net retail portion of franchise taxes paid					$ 1,300	2,500
Cleco Power [Member] | MATS costs
Regulatory Assets and Liabilities [Line Items]
Regulatory Noncurrent Asset, Amortization Period					3 years
Regulatory Assets	2,564		4,270		$ 2,564	4,270				$ 7,100
Cleco Power [Member] | Other
Regulatory Assets and Liabilities [Line Items]
Regulatory Noncurrent Asset, Amortization Period					3 years
Insurance Recoveries					$ 900
Regulatory Assets	484		710		484	710
Cleco Power [Member] | Accumulated deferred fuel
Regulatory Assets and Liabilities [Line Items]
Regulatory Assets	13,980		20,787		$ 13,980	20,787
Percentage of total fuel cost regulated by the LPSC (in hundredths)					76.00%
Increase (Decrease) in deferred fuel costs					$ (6,800)
Cleco Power [Member] | Deferred Fuel Costs, surcharge adjustment, environmental expenses, and timing of collections
Regulatory Assets and Liabilities [Line Items]
Increase (Decrease) in deferred fuel costs					16,000
Cleco Power [Member] | Deferred Fuel Costs, Fuel Surcharges
Regulatory Assets and Liabilities [Line Items]
Increase (Decrease) in deferred fuel costs					5,700
Cleco Power [Member] | Deferred Fuel Costs, Mark-to-Market Value on FTRs
Regulatory Assets and Liabilities [Line Items]
Increase (Decrease) in deferred fuel costs					3,500
Cleco Power [Member] | Approved removal costs deferral | Tree trimming costs
Regulatory Assets and Liabilities [Line Items]
Maximum amount of costs approved to expend and defer											$ 8,000
2017 Tax Reform [Member]
Regulatory Assets and Liabilities [Line Items]
Amount recovered above the actual PPA capacity costs	348,600				348,600
2017 Tax Reform [Member] | Cleco Power [Member]
Regulatory Assets and Liabilities [Line Items]
Amount recovered above the actual PPA capacity costs	$ 348,590		$ 0		$ 348,590	$ 0