Regulatory Assets and Liabilities - Narrative (Details) $ in Thousands		1 Months Ended			3 Months Ended	12 Months Ended
	Apr. 13, 2016 instrument	Jan. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	May 31, 2013 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2011 USD ($) treasury_rate_lock	Dec. 31, 2017 USD ($)	Oct. 31, 2016 USD ($)
Treasury Lock
Regulatory Assets and Liabilities [Line Items]
Number of instruments settled | instrument	2
Postretirement costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets			$ 19,387		$ 19,387	$ 17,399
Financing costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets			8,279		8,279	7,935
TCJA
Regulatory Assets and Liabilities [Line Items]
Regulatory liability			375,000		375,000	375,000		$ 348,600
Net retail portion of franchise taxes paid					26,400
CLECO POWER
Regulatory Assets and Liabilities [Line Items]
Regulatory liability						4,700
Regulatory assets						1,000
Annual reduction to retail customer rates						$ 4,000
CLECO POWER | Treasury Lock
Regulatory Assets and Liabilities [Line Items]
Number of treasury locks | treasury_rate_lock							2
Loss on settlements							$ 26,800
CLECO POWER | Interest Rate Swap
Regulatory Assets and Liabilities [Line Items]
Loss on settlements				$ 3,300
CLECO POWER | Mining costs
Regulatory Assets and Liabilities [Line Items]
Amortization period						11 years 6 months
Regulatory assets			1,274		1,274	$ 0
CLECO POWER | Postretirement costs
Regulatory Assets and Liabilities [Line Items]
Amortization period						8 years
Regulatory assets			140,245		140,245	$ 151,543
CLECO POWER | Tree trimming costs
Regulatory Assets and Liabilities [Line Items]
Maximum amount of costs approved to defer									$ 10,900
Regulatory assets			9,069		9,069	$ 11,341
CLECO POWER | Training costs
Regulatory Assets and Liabilities [Line Items]
Amortization period						50 years
Regulatory assets			6,396		6,396	$ 6,241
CLECO POWER | Surcredits, net
Regulatory Assets and Liabilities [Line Items]
Amortization period						4 years
Regulatory assets			289		289	$ 145
CLECO POWER | AMI deferred revenue requirement
Regulatory Assets and Liabilities [Line Items]
Regulatory assets			3,681		3,681	3,136
CLECO POWER | Emergency declarations
Regulatory Assets and Liabilities [Line Items]
Regulatory assets			2,980		2,980	$ 1,349
CLECO POWER | Production O&M Expenses
Regulatory Assets and Liabilities [Line Items]
Amortization period						3 years
Retail jurisdictional portion						$ 45,000
Increase in other regulatory asset			8,000
CLECO POWER | Production O&M Expenses | MAXIMUM
Regulatory Assets and Liabilities [Line Items]
Regulatory assets						$ 23,000
CLECO POWER | Acquisition costs or Transaction costs
Regulatory Assets and Liabilities [Line Items]
Amortization period						30 years
Regulatory assets			2,230		2,230	$ 2,124
CLECO POWER | Acquisition costs or Transaction costs | Natural Gas Processing Plant
Regulatory Assets and Liabilities [Line Items]
Amortization period						35 years
Regulatory assets			938		938	$ 906
CLECO POWER | Financing costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets			7,923		7,923	7,554
CLECO POWER | Financing costs | Treasury Lock
Regulatory Assets and Liabilities [Line Items]
Regulatory assets							$ 7,400
CLECO POWER | Financing costs | Interest Rate Swap
Regulatory Assets and Liabilities [Line Items]
Regulatory assets				$ 2,900
CLECO POWER | Corporate franchise tax, net
Regulatory Assets and Liabilities [Line Items]
Regulatory liability						$ 1,145
Amortization period						12 months
Regulatory assets			1,416		1,416
CLECO POWER | Energy efficiency
Regulatory Assets and Liabilities [Line Items]
Amortization period						4 years
Regulatory assets			2,585		2,585	$ 2,820
CLECO POWER | Accumulated deferred fuel
Regulatory Assets and Liabilities [Line Items]
Regulatory assets			$ 20,112		$ 20,112	$ 22,910
Percentage of total fuel cost regulated by the LPSC (in hundredths)						76.00%
Cleco Cajun | LPSC
Regulatory Assets and Liabilities [Line Items]
Regulatory liability						$ 800
Annual reduction to retail customer rates		$ 4,000