Schedule I Financial Statements of Cleco Corporation, Condensed Statements of Cash Flows (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
Financing Activities [Abstract]
Cash and cash equivalents at beginning of period	$ 68,246		$ 23,077	$ 68,246
Cash and cash equivalents at end of period		$ 23,077	119,040	23,077	$ 68,246
Cleco Holdings [Member]
Financing Activities [Abstract]
Cash and cash equivalents at beginning of period			1,377
Cash and cash equivalents at end of period		1,377	48,732	1,377
Successor [Member]
Operating Activities [Abstract]
Net cash provided by operating activities		51,322	265,428
Investing Activities [Abstract]
Contributions to tax credit fund		0	(630)
Return of equity investment in tax credit fund		901	7,502
Premiums paid on trust-owned life insurance		0	0
Net cash (used in) provided by investing activities		(161,145)	(190,222)
Financing Activities [Abstract]
Draws on credit facility		15,000	179,000
Payments on credit facility		(15,000)	(179,000)
Issuance of long-term debt		1,680,000	125,000
Repayment of long-term debt		(1,668,268)	(17,896)
Payments of financing costs		(8,655)	(463)
Dividends paid on common stock		(572)	0
Contribution from member		100,720	0
Distributions to member		(88,765)	(84,065)
Other financing		(1,890)	(1,819)
Net cash provided by (used in) financing activities		12,570	20,757
Net increase (decrease) in cash and cash equivalents		(97,253)	95,963
Cash and cash equivalents at beginning of period		120,330	23,077
Cash and cash equivalents at end of period	120,330	23,077	119,040	23,077
Supplementary cash flow information [Abstract]
Interest paid, net of amount capitalized		116,496	118,009
Income taxes (refunded) paid, net		4,263	(6)
Successor [Member] | Cleco Holdings [Member]
Operating Activities [Abstract]
Net cash provided by operating activities		36,811	124,817
Investing Activities [Abstract]
Contributions to tax credit fund		0	(630)
Return of equity investment in tax credit fund		901	7,502
Contribution to subsidiary		(50,000)	0
Premiums paid on trust-owned life insurance		0	0
Net cash (used in) provided by investing activities		(49,099)	6,872
Financing Activities [Abstract]
Draws on credit facility		0	73,000
Payments on credit facility		0	(73,000)
Issuance of long-term debt		1,350,000	0
Repayment of long-term debt		(1,350,000)	0
Payments of financing costs		(3,755)	(269)
Dividends paid on common stock		(572)	0
Contribution from member		100,720	0
Distributions to member		(88,765)	(84,065)
Other financing		0	0
Net cash provided by (used in) financing activities		7,628	(84,334)
Net increase (decrease) in cash and cash equivalents		(4,660)	47,355
Cash and cash equivalents at beginning of period		6,037	1,377
Cash and cash equivalents at end of period	6,037	1,377	48,732	1,377
Supplementary cash flow information [Abstract]
Interest paid, net of amount capitalized		26,264	52,026
Income taxes (refunded) paid, net		4,263	(6)
Supplementary non-cash investing and financing activities [Abstract]
Non-cash distribution from subsidiary		0	$ 13,000
Predecessor [Member]
Operating Activities [Abstract]
Net cash provided by operating activities	129,780				361,022
Investing Activities [Abstract]
Contributions to tax credit fund	0				(9,966)
Return of equity investment in tax credit fund	476				2,128
Premiums paid on trust-owned life insurance	0				(3,607)
Net cash (used in) provided by investing activities	(36,811)				(167,951)
Financing Activities [Abstract]
Draws on credit facility	3,000				120,000
Payments on credit facility	(10,000)				(163,000)
Issuance of long-term debt	0				75,000
Repayment of long-term debt	(8,546)				(100,824)
Payments of financing costs	(43)				(693)
Dividends paid on common stock	(24,579)				(97,283)
Contribution from member	0				0
Distributions to member	0				0
Other financing	(717)				(2,448)
Net cash provided by (used in) financing activities	(40,885)				(169,248)
Net increase (decrease) in cash and cash equivalents	52,084				23,823
Cash and cash equivalents at beginning of period	68,246	120,330		68,246	44,423
Cash and cash equivalents at end of period	120,330				68,246
Supplementary cash flow information [Abstract]
Interest paid, net of amount capitalized	2,478				74,349
Income taxes (refunded) paid, net	(481)				1,434
Predecessor [Member] | Cleco Holdings [Member]
Operating Activities [Abstract]
Net cash provided by operating activities	34,904				128,909
Investing Activities [Abstract]
Contributions to tax credit fund	0				(9,966)
Return of equity investment in tax credit fund	476				2,128
Contribution to subsidiary	0				0
Premiums paid on trust-owned life insurance	0				(3,607)
Net cash (used in) provided by investing activities	476				(11,445)
Financing Activities [Abstract]
Draws on credit facility	3,000				57,000
Payments on credit facility	(10,000)				(80,000)
Issuance of long-term debt	0				0
Repayment of long-term debt	0				0
Payments of financing costs	0				0
Dividends paid on common stock	(24,579)				(97,283)
Contribution from member	0				0
Distributions to member	0				0
Other financing	0				(14)
Net cash provided by (used in) financing activities	(31,579)				(120,297)
Net increase (decrease) in cash and cash equivalents	3,801				(2,833)
Cash and cash equivalents at beginning of period	2,236	$ 6,037		$ 2,236	5,069
Cash and cash equivalents at end of period	6,037				2,236
Supplementary cash flow information [Abstract]
Interest paid, net of amount capitalized	126				130
Income taxes (refunded) paid, net	1				1,464
Supplementary non-cash investing and financing activities [Abstract]
Non-cash distribution from subsidiary	$ 0				$ 33,661