Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended			6 Months Ended	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Apr. 12, 2016	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Operating revenue [Abstract]
Electric operations	$ 317,589	$ 323,707
Other operations	21,282	18,976
Affiliate revenue	0	0
Gross operating revenue	338,871	342,683
Electric customer credits	(372)	177
Operating revenue, net	338,499	342,860
Operating expenses [Abstract]
Fuel used for electric generation	103,217	101,908
Power purchased for utility customers	39,355	36,058
Other operations	27,957	35,361
Maintenance	18,031	19,412
Depreciation and amortization	42,228	42,535
Taxes other than income taxes	12,414	12,574
Merger transaction and commitment costs	185	1,869
Total operating expenses	243,387	249,717
Operating (loss) income	95,112	93,143
Interest income	354	318
Allowance for equity funds used during construction	2,096	1,308
Other income	2,557	658
Other expense	(1,299)	(248)
Interest charges [Abstract]
Interest charges, including amortization of debt issuance costs, premiums, and discounts, net	31,110	32,233
Allowance for borrowed funds used during construction	(648)	(375)
Total interest charges	30,462	31,858
(Loss) income before income taxes	68,358	63,321
Federal and state income tax (benefit) expense	23,054	23,700
Net (loss) income	45,304	39,621			$ 77,041
Predecessor
Operating revenue [Abstract]
Electric operations			$ 281,154
Other operations			19,080
Affiliate revenue			0
Gross operating revenue			300,234
Electric customer credits			(364)
Operating revenue, net			299,870
Operating expenses [Abstract]
Fuel used for electric generation			96,378
Power purchased for utility customers			27,249
Other operations			33,563
Maintenance			29,813
Depreciation and amortization			44,076
Taxes other than income taxes			14,611
Merger transaction and commitment costs			34,912
Gain on sale of asset			(1,095)
Total operating expenses			279,507
Operating (loss) income			20,363
Interest income			265
Allowance for equity funds used during construction			723
Other income			870
Other expense			(590)
Interest charges [Abstract]
Interest charges, including amortization of debt issuance costs, premiums, and discounts, net			22,330
Allowance for borrowed funds used during construction			(207)
Total interest charges			22,123
(Loss) income before income taxes			(492)
Federal and state income tax (benefit) expense			3,468
Net (loss) income			$ (3,960)
Successor
Operating revenue [Abstract]
Electric operations				$ 553,634	839,080
Other operations				33,110	59,627
Affiliate revenue				0	0
Gross operating revenue				586,744	898,707
Electric customer credits				(381)	(1,045)
Operating revenue, net				586,363	897,662
Operating expenses [Abstract]
Fuel used for electric generation				168,159	261,063
Power purchased for utility customers				60,439	114,675
Other operations				59,633	89,201
Maintenance				42,317	66,955
Depreciation and amortization				76,695	124,630
Taxes other than income taxes				22,953	36,790
Merger transaction and commitment costs				173,172	187
Gain on sale of asset				0	0
Total operating expenses				603,368	693,501
Operating (loss) income				(17,005)	204,161
Interest income				515	1,046
Allowance for equity funds used during construction				2,057	4,446
Other income				2,395	4,402
Other expense				(435)	(1,833)
Interest charges [Abstract]
Interest charges, including amortization of debt issuance costs, premiums, and discounts, net				58,926	94,077
Allowance for borrowed funds used during construction				(603)	(1,277)
Total interest charges				58,323	92,800
(Loss) income before income taxes				(70,796)	119,422
Federal and state income tax (benefit) expense				(28,502)	42,381
Net (loss) income				$ (42,294)	77,041
Cleco Power [Member]
Operating revenue [Abstract]
Electric operations	320,009	326,281			847,417	$ 839,593
Other operations	20,768	18,460			58,083	50,638
Affiliate revenue	209	213			649	669
Gross operating revenue	340,986	344,954			906,149	890,900
Electric customer credits	(372)	177			(1,045)	(745)
Operating revenue, net	340,614	345,131			905,104	890,155
Operating expenses [Abstract]
Fuel used for electric generation	103,217	101,908			261,063	264,537
Power purchased for utility customers	39,355	36,058			114,675	87,688
Other operations	28,680	35,886			90,453	94,566
Maintenance	17,812	19,326			66,496	71,818
Depreciation and amortization	40,049	40,353			118,280	115,196
Taxes other than income taxes	12,008	12,180			35,412	36,096
Merger transaction and commitment costs					0	151,501
Gain on sale of asset					0	(1,095)
Total operating expenses	241,121	245,711			686,379	820,307
Operating (loss) income	99,493	99,420			218,725	69,848
Interest income	332	264			926	590
Allowance for equity funds used during construction	2,096	1,308			4,446	2,780
Other income	1,463	629			1,839	828
Other expense	(1,299)	(445)			(1,833)	(1,082)
Interest charges [Abstract]
Interest charges, including amortization of debt issuance costs, premiums, and discounts, net	17,789	19,552			53,931	58,587
Allowance for borrowed funds used during construction	(648)	(375)			(1,277)	(810)
Total interest charges	17,141	19,177			52,654	57,777
(Loss) income before income taxes	84,944	81,999			171,449	15,187
Federal and state income tax (benefit) expense	30,092	29,427			63,010	2,965
Net (loss) income	$ 54,852	$ 52,572			$ 108,439	$ 12,222