Regulatory Assets and Liabilities - Schedule of Regulatory Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Regulatory Assets [Line Items]
Total regulatory assets, net	$ 334,159	$ 330,582
Cleco Power
Regulatory Assets [Line Items]
Regulatory assets	257,473	273,220
Total regulatory assets, net	158,742	146,774
Cleco Power | Mining costs
Regulatory Assets [Line Items]
Regulatory assets	1,912	3,823
Cleco Power | Interest costs
Regulatory Assets [Line Items]
Regulatory assets	4,271	4,499
Cleco Power | AROs
Regulatory Assets [Line Items]
Regulatory assets	2,961	2,762
Cleco Power | Postretirement costs
Regulatory Assets [Line Items]
Regulatory assets	133,584	142,764
Cleco Power | Tree trimming costs
Regulatory Assets [Line Items]
Regulatory assets	8,535	7,193
Cleco Power | Training costs
Regulatory Assets [Line Items]
Regulatory assets	6,435	6,552
Cleco Power | Surcredits, net
Regulatory Assets [Line Items]
Regulatory assets	289	2,173
Cleco Power | AMI deferred revenue requirement
Regulatory Assets [Line Items]
Regulatory assets	3,817	4,227
Cleco Power | Emergency declarations
Regulatory Assets [Line Items]
Regulatory assets	3,378	4,131
Cleco Power | Production operations and maintenance expenses
Regulatory Assets [Line Items]
Regulatory assets	5,039	8,625
Cleco Power | AFUDC equity gross-up
Regulatory Assets [Line Items]
Regulatory assets	71,530	71,205
Cleco Power | Acquisition/ transaction costs
Regulatory Assets [Line Items]
Regulatory assets	2,257	2,336
Cleco Power | Acquisition/ transaction costs | Coughlin transaction costs
Regulatory Assets [Line Items]
Regulatory assets	945	968
Cleco Power | Financing costs
Regulatory Assets [Line Items]
Regulatory assets	8,015	8,293
Cleco Power | MISO integration costs
Regulatory Assets [Line Items]
Regulatory assets	0	468
Cleco Power | Corporate franchise tax, net
Regulatory Assets [Line Items]
Regulatory assets	1,001	153
Cleco Power | MATS costs
Regulatory Assets [Line Items]
Regulatory assets	0	2,564
Cleco Power | Non-service cost of postretirement benefits
Regulatory Assets [Line Items]
Regulatory assets	3,484	0
Cleco Power | Other
Regulatory Assets [Line Items]
Regulatory assets	20	484
Cleco Power | Accumulated deferred fuel
Regulatory Assets [Line Items]
Regulatory assets	39,898	13,980
Cleco Holdings | Postretirement costs
Regulatory Assets [Line Items]
Regulatory assets	19,884	21,375
Cleco Holdings | Financing costs
Regulatory Assets [Line Items]
Regulatory assets	8,365	8,623
Cleco Holdings | Fair value of long-term debt
Regulatory Assets [Line Items]
Regulatory assets	140,812	147,145
Cleco Holdings | Debt issuance costs
Regulatory Assets [Line Items]
Regulatory assets	$ 6,356	$ 6,665