Litigation, Other Commitments and Contingencies, and Disclosures about Guarantees - Litigation (Details) $ in Thousands		1 Months Ended					24 Months Ended
	May 22, 2018 USD ($)	Sep. 30, 2016	Jun. 30, 2016 petition	Sep. 30, 2015 USD ($)	Nov. 30, 2014	Nov. 30, 2013	Dec. 31, 2017 USD ($)	Sep. 30, 2018 USD ($)	Feb. 28, 2017 USD ($)
Loss Contingencies [Line Items]
Provision for rate refund							$ 4,206	$ 26,923
Loss contingency, estimate of possible loss								4,600
FERC | MISO Transmission Rates
Loss Contingencies [Line Items]
Public utilities, requested rate increase (decrease), percentage (in hundredths)					0.50%
Gulf Coast Spinning start up costs
Loss Contingencies [Line Items]
Allegations by plaintiff, failure to perform				$ 6,500
Gulf Coast Spinning construction of cotton spinning facility
Loss Contingencies [Line Items]
Allegations by plaintiff, failure to perform				$ 60,000
CLECO POWER
Loss Contingencies [Line Items]
Provision for rate refund							4,206	26,923
CLECO POWER | LPSC 2016-2017 Fuel Audit
Loss Contingencies [Line Items]
Fuel costs							$ 536,200
CLECO POWER | LPSC 2016-2017 EAC Audit
Loss Contingencies [Line Items]
Loss contingency, damages sought, value	$ 30,700
CLECO POWER | LPSC Nov 2010-Dec 2015 EAC Audit
Loss Contingencies [Line Items]
Number of petitions filed with the U.S. Court of Appeals | petition			6
CLECO POWER | FERC | MISO Transmission Rates
Loss Contingencies [Line Items]
Public utilities, approved return on equity, percentage (In hundredths)		10.32%				12.38%
Public utilities, proposed return on equity, percentage (in hundredths)			9.70%			6.68%
Provision for rate refund								$ 2,100	$ 1,200