Schedule II Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Apr. 12, 2016	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Allowance for Uncollectible Accounts [Member] | Cleco Power [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	$ 2,674		$ 7,199	$ 2,674	$ 922
Additions charged to costs and expenses			4,179	5,511	2,986
Uncollectible account write-offs less recoveries			9,921	986	1,234
Balance at end of period		$ 7,199	1,457	7,199	2,674
Unrestricted Storm Reserve [Member] | Cleco Power [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	2,801		2,607	2,801	3,322
Additions			4,000	71	0
Deductions			2,421	265	521
Balance at end of period		2,607	4,186	2,607	2,801
Restricted Storm Reserve [Member] | Cleco Power [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	16,177		17,385	16,177	14,916
Additions			1,084	1,208	1,261
Deductions			4,000	0	0
Balance at end of period		17,385	14,469	17,385	16,177
Successor [Member] | Allowance for Uncollectible Accounts [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period		3,336	7,199
Additions charged to costs and expenses		4,348	4,179
Uncollectible account write-offs less recoveries		485	9,921
Balance at end of period	3,336	7,199	1,457	7,199
Successor [Member] | Unrestricted Storm Reserve [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period		2,536	2,607
Additions		71	4,000
Deductions		0	2,421
Balance at end of period	2,536	2,607	4,186	2,607
Successor [Member] | Restricted Storm Reserve [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period		16,515	17,385
Additions		870	1,084
Deductions		0	4,000
Balance at end of period	16,515	17,385	$ 14,469	17,385
Predecessor [Member] | Allowance for Uncollectible Accounts [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	2,674	3,336		2,674	922
Additions charged to costs and expenses	1,163				2,986
Uncollectible account write-offs less recoveries	501				1,234
Balance at end of period	3,336				2,674
Predecessor [Member] | Unrestricted Storm Reserve [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	2,801	2,536		2,801	3,322
Additions	0				0
Deductions	265				521
Balance at end of period	2,536				2,801
Predecessor [Member] | Restricted Storm Reserve [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	16,177	$ 16,515		$ 16,177	14,916
Additions	338				1,261
Deductions	0				0
Balance at end of period	$ 16,515				$ 16,177