Regulatory Assets and Liabilities - Schedule of Regulatory Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Regulatory Assets [Line Items]
Total regulatory assets, net	$ 328,537	$ 307,374
Fair value of long-term debt
Regulatory Assets [Line Items]
Regulatory assets	130,847	138,701
Postretirement costs
Regulatory Assets [Line Items]
Regulatory assets	17,896	19,387
Financing costs
Regulatory Assets [Line Items]
Regulatory assets	8,021	8,279
Debt issuance costs
Regulatory Assets [Line Items]
Regulatory assets	5,826	6,252
CLECO POWER
Regulatory Assets [Line Items]
Total regulatory assets, net	165,947	134,755
CLECO POWER | Mining costs
Regulatory Assets [Line Items]
Regulatory assets	0	1,274
CLECO POWER | Interest costs
Regulatory Assets [Line Items]
Regulatory assets	4,021	4,208
CLECO POWER | AROs
Regulatory Assets [Line Items]
Regulatory assets	3,523	3,099
CLECO POWER | Postretirement costs
Regulatory Assets [Line Items]
Regulatory assets	134,412	140,245
CLECO POWER | Tree trimming costs
Regulatory Assets [Line Items]
Regulatory assets	10,607	9,069
CLECO POWER | Training costs
Regulatory Assets [Line Items]
Regulatory assets	6,279	6,396
CLECO POWER | Surcredits, net
Regulatory Assets [Line Items]
Regulatory assets	289	289
CLECO POWER | AMI deferred revenue requirement
Regulatory Assets [Line Items]
Regulatory assets	3,272	3,681
CLECO POWER | Emergency declarations
Regulatory Assets [Line Items]
Regulatory assets	1,750	2,980
CLECO POWER | Production operations and maintenance expenses
Regulatory Assets [Line Items]
Regulatory assets	9,199	12,245
CLECO POWER | AFUDC equity gross-up
Regulatory Assets [Line Items]
Regulatory assets	73,541	71,952
CLECO POWER | Acquisition/ transaction costs
Regulatory Assets [Line Items]
Regulatory assets	2,151	2,230
CLECO POWER | Acquisition/ transaction costs | Coughlin transaction costs
Regulatory Assets [Line Items]
Regulatory assets	915	938
CLECO POWER | Financing costs
Regulatory Assets [Line Items]
Regulatory assets	7,646	7,923
CLECO POWER | Corporate franchise tax, net
Regulatory Assets [Line Items]
Regulatory assets	864	1,416
CLECO POWER | Non-service cost of postretirement benefits
Regulatory Assets [Line Items]
Regulatory assets	6,650	4,629
CLECO POWER | Energy efficiency
Regulatory Assets [Line Items]
Regulatory assets		2,585
CLECO POWER | Accumulated deferred fuel
Regulatory Assets [Line Items]
Regulatory assets	$ 56,056	$ 20,112