Consolidated Statements of Income - 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
Predecessor [Member]
Operating revenue [Abstract]
Electric operations	$ 281,154				$ 1,142,389
Other operations	19,080				69,186
Affiliate revenue	0				0
Gross operating revenue	300,234				1,211,575
Electric customer credits	(364)				(2,173)
Operating revenue, net	299,870				1,209,402
Operating expenses [Abstract]
Fuel used for electric generation	96,378				373,117
Power purchased for utility customers	27,249				130,095
Other operations	33,563				127,410
Maintenance	29,813				88,137
Depreciation and amortization	44,076				149,579
Taxes other than income taxes	14,611				49,134
Merger transaction and commitment costs	34,912				4,591
Gain on sale of assets	(1,095)				0
Total operating expenses	279,507				922,063
Operating income (loss)	20,363				287,339
Interest income	265				895
Allowance for equity funds used during construction	723				3,063
Other income	870				1,443
Other expense	(590)				(3,376)
Interest charges [Abstract]
Interest charges, including amortization of debt issuance costs, premiums, and discounts, net	22,330				78,877
Allowance for borrowed funds used during construction	(207)				(886)
Total interest charges	22,123				77,991
Income (loss) before income taxes	(492)				211,373
Federal and state income tax expense (benefit)	3,468				77,704
Net income (loss)	$ (3,960)				133,669
Successor [Member]
Operating revenue [Abstract]
Electric operations		$ 802,592	$ 1,097,632
Other operations		51,562	79,580
Affiliate revenue		0	0
Gross operating revenue		854,154	1,177,212
Electric customer credits		(1,149)	(1,566)
Operating revenue, net		853,005	1,175,646
Operating expenses [Abstract]
Fuel used for electric generation		250,142	339,346
Power purchased for utility customers		92,337	152,913
Other operations		90,313	125,699
Maintenance		63,944	88,129
Depreciation and amortization		109,739	166,439
Taxes other than income taxes		35,543	48,546
Merger transaction and commitment costs		174,696	287
Gain on sale of assets		0	(2)
Total operating expenses		816,714	921,357
Operating income (loss)		36,291	254,289
Interest income		840	1,424
Allowance for equity funds used during construction		3,735	8,320
Other income		3,350	6,474
Other expense		(1,385)	(2,435)
Interest charges [Abstract]
Interest charges, including amortization of debt issuance costs, premiums, and discounts, net		90,852	125,200
Allowance for borrowed funds used during construction		(1,086)	(2,287)
Total interest charges		89,766	122,913
Income (loss) before income taxes		(46,935)	145,159
Federal and state income tax expense (benefit)		(22,822)	7,079
Net income (loss)		$ (24,113)	138,080
Cleco Power [Member]
Operating revenue [Abstract]
Electric operations			1,108,389	$ 1,091,229	1,142,389
Other operations			77,522	68,573	67,109
Affiliate revenue			851	884	1,142
Gross operating revenue			1,186,762	1,160,686	1,210,640
Electric customer credits			(1,566)	(1,513)	(2,173)
Operating revenue, net			1,185,196	1,159,173	1,208,467
Operating expenses [Abstract]
Fuel used for electric generation			339,346	346,520	373,117
Power purchased for utility customers			152,913	119,586	130,095
Other operations			123,192	125,892	128,697
Maintenance			87,574	93,340	87,416
Depreciation and amortization			157,999	146,142	147,839
Taxes other than income taxes			46,539	48,287	47,102
Merger transaction and commitment costs			0	151,501	0
Gain on sale of assets			0	(1,095)	0
Total operating expenses			907,563	1,030,173	914,266
Operating income (loss)			277,633	129,000	294,201
Interest income			1,283	860	725
Allowance for equity funds used during construction			8,320	4,458	3,063
Other income			2,990	1,601	1,764
Other expense			(2,795)	(1,976)	(2,549)
Interest charges [Abstract]
Interest charges, including amortization of debt issuance costs, premiums, and discounts, net			71,649	77,739	77,446
Allowance for borrowed funds used during construction			(2,287)	(1,293)	(886)
Total interest charges			69,362	76,446	76,560
Income (loss) before income taxes			218,069	57,497	220,644
Federal and state income tax expense (benefit)			67,331	18,369	79,294
Net income (loss)			$ 150,738	$ 39,128	$ 141,350