Disclosures about Segments (Details) $ in Thousands	3 Months Ended			6 Months Ended	9 Months Ended
	Sep. 30, 2017 USD ($) entity	Sep. 30, 2016 USD ($)	Apr. 12, 2016 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) entity	Dec. 31, 2016 USD ($)	Apr. 13, 2016 USD ($)
Segment Reporting Information [Line Items]
Number of transmission interconnection facility subsidiaries | entity	2				2
Revenue [Abstract]
Electric operations	$ 317,589	$ 323,707
Other operations	21,282	18,976
Electric customer credits	(372)	177
Affiliate revenue	0	0
Operating revenue, net	338,499	342,860
Depreciation and amortization	42,228	42,535
Merger transaction and commitment costs	185	1,869
Interest charges	30,462	31,858
Interest income	354	318
Federal and state income tax (benefit) expense	23,054	23,700
Net (loss) income	45,304	39,621			$ 77,041
Equity investment in investees	18,172				18,172	$ 18,672
Goodwill	1,490,797				1,490,797	1,490,797	$ 1,490,797
Total Segment Assets	6,397,701				6,397,701	6,343,144
Operating Segments [Member] | Other [Member]
Revenue [Abstract]
Electric operations	(2,420)	(2,574)
Other operations	514	517
Electric customer credits	0	0
Affiliate revenue	13,517	13,060
Operating revenue, net	11,611	11,003
Depreciation and amortization	2,179	2,182
Merger transaction and commitment costs	185	1,869
Interest charges	13,331	12,709
Interest income	31	82
Federal and state income tax (benefit) expense	(7,038)	(5,728)
Net (loss) income	(9,548)	(12,952)
Operating Segments [Member] | Cleco Power [Member]
Revenue [Abstract]
Electric operations	320,009	326,281
Other operations	20,768	18,460
Electric customer credits	(372)	177
Affiliate revenue	209	213
Operating revenue, net	340,614	345,131
Depreciation and amortization	40,049	40,353
Merger transaction and commitment costs	0	0
Interest charges	17,141	19,177
Interest income	332	264
Federal and state income tax (benefit) expense	30,092	29,427
Net (loss) income	54,852	52,572
Intersegment Elimination [Member]
Revenue [Abstract]
Electric operations	0	0
Other operations	0	(1)
Electric customer credits	0	0
Affiliate revenue	(13,726)	(13,273)
Operating revenue, net	(13,726)	(13,274)
Depreciation and amortization	0	0
Merger transaction and commitment costs	0	0
Interest charges	(10)	(28)
Interest income	(9)	(28)
Federal and state income tax (benefit) expense	0	1
Net (loss) income	0	$ 1
Successor
Revenue [Abstract]
Electric operations				$ 553,634	839,080
Other operations				33,110	59,627
Electric customer credits				(381)	(1,045)
Affiliate revenue				0	0
Operating revenue, net				586,363	897,662
Depreciation and amortization				76,695	124,630
Merger transaction and commitment costs				173,172	187
Interest charges				58,323	92,800
Interest income				515	1,046
Federal and state income tax (benefit) expense				(28,502)	42,381
Net (loss) income				(42,294)	77,041
Additions to property, plant, and equipment				102,677	185,609
Equity investment in investees	18,172				18,172	18,672
Goodwill						1,490,797
Total Segment Assets	6,397,701				6,397,701	6,343,144
Successor | Operating Segments [Member] | Other [Member]
Revenue [Abstract]
Electric operations				(4,805)	(8,337)
Other operations				965	1,544
Electric customer credits				0	0
Affiliate revenue				23,823	41,882
Operating revenue, net				19,983	35,089
Depreciation and amortization				5,198	6,351
Merger transaction and commitment costs				21,671	187
Interest charges				22,430	40,297
Interest income				177	271
Federal and state income tax (benefit) expense				(18,474)	(20,629)
Net (loss) income				(32,968)	(31,398)
Additions to property, plant, and equipment				393	2,005
Equity investment in investees	0				0	0
Goodwill	0				0	0
Total Segment Assets	592,681				592,681	614,959
Successor | Operating Segments [Member] | Cleco Power [Member]
Revenue [Abstract]
Electric operations				558,439	847,417
Other operations				32,145	58,083
Electric customer credits				(381)	(1,045)
Affiliate revenue				406	649
Operating revenue, net				590,609	905,104
Depreciation and amortization				71,498	118,280
Merger transaction and commitment costs				151,501	0
Interest charges				35,937	52,654
Interest income				382	926
Federal and state income tax (benefit) expense				(10,028)	63,010
Net (loss) income				(9,326)	108,439
Additions to property, plant, and equipment				102,284	183,604
Equity investment in investees	18,172				18,172	18,672
Goodwill	1,490,797				1,490,797	1,490,797
Total Segment Assets	5,822,302				5,822,302	5,758,245
Successor | Intersegment Elimination [Member]
Revenue [Abstract]
Electric operations				0	0
Other operations				0	0
Electric customer credits				0	0
Affiliate revenue				(24,229)	(42,531)
Operating revenue, net				(24,229)	(42,531)
Depreciation and amortization				(1)	(1)
Merger transaction and commitment costs				0	0
Interest charges				(44)	(151)
Interest income				(44)	(151)
Federal and state income tax (benefit) expense				0	0
Net (loss) income				0	0
Additions to property, plant, and equipment				$ 0	0
Equity investment in investees	0				0	0
Goodwill	0				0	0
Total Segment Assets	$ (17,282)				$ (17,282)	$ (30,060)
Predecessor
Revenue [Abstract]
Electric operations			$ 281,154
Other operations			19,080
Electric customer credits			(364)
Affiliate revenue			0
Operating revenue, net			299,870
Depreciation and amortization			44,076
Merger transaction and commitment costs			34,912
Interest charges			22,123
Interest income			265
Federal and state income tax (benefit) expense			3,468
Net (loss) income			(3,960)
Additions to property, plant, and equipment			42,392
Predecessor | Operating Segments [Member] | Other [Member]
Revenue [Abstract]
Electric operations			0
Other operations			587
Electric customer credits			0
Affiliate revenue			15,024
Operating revenue, net			15,611
Depreciation and amortization			377
Merger transaction and commitment costs			34,928
Interest charges			295
Interest income			69
Federal and state income tax (benefit) expense			(9,525)
Net (loss) income			(25,508)
Additions to property, plant, and equipment			39
Predecessor | Operating Segments [Member] | Cleco Power [Member]
Revenue [Abstract]
Electric operations			281,154
Other operations			18,493
Electric customer credits			(364)
Affiliate revenue			263
Operating revenue, net			299,546
Depreciation and amortization			43,698
Merger transaction and commitment costs			0
Interest charges			21,840
Interest income			208
Federal and state income tax (benefit) expense			12,993
Net (loss) income			21,548
Additions to property, plant, and equipment			42,353
Predecessor | Intersegment Elimination [Member]
Revenue [Abstract]
Electric operations			0
Other operations			0
Electric customer credits			0
Affiliate revenue			(15,287)
Operating revenue, net			(15,287)
Depreciation and amortization			1
Merger transaction and commitment costs			(16)
Interest charges			(12)
Interest income			(12)
Federal and state income tax (benefit) expense			0
Net (loss) income			0
Additions to property, plant, and equipment			$ 0