Regulatory Assets and Liabilities - Summary of Regulatory Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Feb. 28, 2016
Regulatory Assets and Liabilities [Line Items]
Total regulatory assets, net	$ 307,374	$ 330,582
Postretirement costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	19,387	21,375
Financing costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	8,279	8,623
Fair value of long-term debt
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	138,701	147,145
Debt issuance costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	6,252	6,665
TCJA
Regulatory Assets and Liabilities [Line Items]
Regulatory liabilities	(375,000)	(348,600)
CLECO POWER
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	275,172	273,220
Total regulatory assets, net	134,755	146,774
CLECO POWER | Total state regulatory asset — income taxes
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	141,136	142,788
CLECO POWER | AFUDC
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	134,369	129,953
CLECO POWER | Mining costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	$ 1,274	3,823
REMAINING RECOVERY PERIOD (YRS.)	6 months
CLECO POWER | Interest costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	$ 4,208	4,499
CLECO POWER | AROs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	3,099	2,762
CLECO POWER | Postretirement costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	140,245	142,764
CLECO POWER | Tree trimming costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	9,069	7,193
CLECO POWER | Training costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	$ 6,396	6,552
REMAINING RECOVERY PERIOD (YRS.)	41 years
CLECO POWER | Surcredits, net
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	$ 289	2,173
CLECO POWER | AMI deferred revenue requirement
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	$ 3,681	4,227
REMAINING RECOVERY PERIOD (YRS.)	7 years
CLECO POWER | Emergency declarations
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	$ 2,980	4,131
REMAINING RECOVERY PERIOD (YRS.)	1 year 6 months
CLECO POWER | Production operations and maintenance expenses
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	$ 12,245	8,625
CLECO POWER | AFUDC equity gross-up
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	71,952	71,205
CLECO POWER | Acquisition costs or Transaction costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	$ 2,230	2,336
REMAINING RECOVERY PERIOD (YRS.)	21 years
CLECO POWER | Acquisition costs or Transaction costs | Natural Gas Processing Plant
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	$ 938	968
REMAINING RECOVERY PERIOD (YRS.)	30 years 6 months
CLECO POWER | Financing costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	$ 7,923	8,293
CLECO POWER | MISO integration costs | Natural Gas Processing Plant
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	0	468
CLECO POWER | Corporate franchise tax, net
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	1,416	153
CLECO POWER | MATS Costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	0	2,564	$ 7,100
CLECO POWER | Non-service cost of postretirement benefits
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	4,629	0
CLECO POWER | Energy Efficiency
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	2,585	0
CLECO POWER | Other
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	13	484
CLECO POWER | Accumulated deferred fuel
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	20,112	13,980
CLECO POWER | Total federal regulatory liability — income taxes
Regulatory Assets and Liabilities [Line Items]
Regulatory liabilities	(55,922)	(64,205)
CLECO POWER | TCJA
Regulatory Assets and Liabilities [Line Items]
Regulatory liabilities	(374,961)	(348,590)
CLECO POWER | Total investment tax credit
Regulatory Assets and Liabilities [Line Items]
Regulatory liabilities	(159)	(372)
CLECO POWER | Total regulatory (liabilities) assets — deferred taxes, net
Regulatory Assets and Liabilities [Line Items]
Regulatory liabilities	(155,537)	(140,426)
CLECO POWER | Other
Regulatory Assets and Liabilities [Line Items]
Regulatory liabilities	$ (4,992)	$ 0