Summary of Significant Accounting Policies - Changes in Allowance for Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 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	$ 2,040	$ 2,123	$ 2,758	$ 3,005
Current period provision	616	1,137	2,490	3,634
Charge-offs	(1,583)	0	(4,442)	(4,091)
Recovery	261	226	528	867
Accounts receivable, ending balance	1,334	3,486	1,334	3,486
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
Receivable, Allowance For Credit Loss [Roll Forward]
Total, beginning balance	3,678	3,761	4,396	4,255
Current period provision	616	1,137	2,490	4,022
Charge-offs	(1,583)	0	(4,442)	(4,091)
Recovery	261	226	528	867
Total, ending balance	2,972	5,124	2,972	5,124
CLECO POWER
ACCOUNTS RECEIVABLE
Accounts receivable, beginning balance	2,040	2,123	2,758	3,005
Current period provision	616	1,137	2,490	3,634
Charge-offs	(1,583)	0	(4,442)	(4,091)
Recovery	261	226	528	867
Accounts receivable, ending balance	$ 1,334	3,486	$ 1,334	3,486
Accounting Standards Update 2016-13 | CECL adoption
ACCOUNTS RECEIVABLE
Accounts receivable, beginning balance		0		71
Receivable, Allowance For Credit Loss [Roll Forward]
Total, beginning balance		0		71
Accounting Standards Update 2016-13 | CLECO POWER | CECL adoption
ACCOUNTS RECEIVABLE
Accounts receivable, beginning balance		0
Accounts receivable, ending balance		$ 71		$ 71