Summary of Significant Accounting Policies - Changes in Allowance for Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Financing Receivable, Allowance for Credit Loss [Line Items]
Receivable, threshold period past due	20 days		20 days
ACCOUNTS RECEIVABLE
Accounts receivable, beginning balance	$ 1,334	$ 3,486	$ 2,758	$ 3,005
Current period provision	567	2,041	3,057	5,675
Charge-offs	(730)	0	(5,172)	(4,091)
Recovery	586	54	1,114	921
Accounts receivable, ending balance	1,757	5,581	1,757	5,581
OTHER
Financing receivable, beginning balance	1,638	1,638	1,638	1,250
Current period provision	0	0	0	388
Charge-offs	0	0	0	0
Recovery	0	0	0	0
Financing receivable, ending balance	1,638	1,638	1,638	1,638
TOTAL
Total, beginning balance	2,972	5,124	4,396	4,255
Current period provision	567	2,041	3,057	6,063
Charge-offs	(730)	0	(5,172)	(4,091)
Recovery	586	54	1,114	921
Total, ending balance	3,395	7,219	3,395	7,219
CLECO POWER
ACCOUNTS RECEIVABLE
Accounts receivable, beginning balance	1,334	3,486	2,758	3,005
Current period provision	567	2,041	3,057	5,675
Charge-offs	(730)	0	(5,172)	(4,091)
Recovery	586	54	1,114	921
Accounts receivable, ending balance	$ 1,757	5,581	$ 1,757	5,581
Accounting Standards Update 2016-13 | CECL adoption
ACCOUNTS RECEIVABLE
Accounts receivable, beginning balance		0		71
TOTAL
Total, beginning balance		0		71
Accounting Standards Update 2016-13 | CLECO POWER | CECL adoption
ACCOUNTS RECEIVABLE
Accounts receivable, beginning balance		$ 0		$ 71