Summary of Significant Accounting Policies - Restricted Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2018	Dec. 31, 2017
Restricted Cash and Cash Equivalents Items [Line Items]
Current	$ 5,247	$ 13,081
Non-current	18,850	20,081
Total restricted cash and cash equivalents	24,097	33,162
Cleco Katrina/Rita’s storm recovery bonds
Restricted Cash and Cash Equivalents Items [Line Items]
Current	3,504	8,597
Charitable contributions
Restricted Cash and Cash Equivalents Items [Line Items]
Current	1,200	1,200
Non-current	2,841	3,575
Rate credit escrow
Restricted Cash and Cash Equivalents Items [Line Items]
Current	543	3,284
Non-current	822	2,029
Diversified Lands’ mitigation escrow
Restricted Cash and Cash Equivalents Items [Line Items]
Non-current	22	21
Future storm restoration costs
Restricted Cash and Cash Equivalents Items [Line Items]
Non-current	15,165	14,456
Cleco Katrina/Rita Bond Principal Payments
Restricted Cash and Cash Equivalents Items [Line Items]
Increase (decrease) in restricted cash	(19,200)
Cleco Katrina/Rita Bond Interest Payments
Restricted Cash and Cash Equivalents Items [Line Items]
Increase (decrease) in restricted cash	(2,600)
Cleco Katrina/Rita storm recovery collections, net of administration fees
Restricted Cash and Cash Equivalents Items [Line Items]
Increase (decrease) in restricted cash	16,700
CLECO POWER
Restricted Cash and Cash Equivalents Items [Line Items]
Current	5,247	13,081
Non-current	18,828	20,060
Total restricted cash and cash equivalents	24,075	33,141
CLECO POWER \| Cleco Katrina/Rita’s storm recovery bonds
Restricted Cash and Cash Equivalents Items [Line Items]
Current	3,504	8,597
CLECO POWER \| Charitable contributions
Restricted Cash and Cash Equivalents Items [Line Items]
Current	1,200	1,200
Non-current	2,841	3,575
CLECO POWER \| Rate credit escrow
Restricted Cash and Cash Equivalents Items [Line Items]
Current	543	3,284
Non-current	822	2,029
CLECO POWER \| Future storm restoration costs
Restricted Cash and Cash Equivalents Items [Line Items]
Non-current	$ 15,165	$ 14,456

The net cash inflow or outflow for the increase (decrease) associated with funds that are not available for withdrawal or use (such as funds held in escrow) and are associated with underlying transactions that are classified as investing activities.

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