Disclosures about Segments (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018 USD ($) entity	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($) entity	Sep. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)	Apr. 13, 2016 USD ($)
Segment Reporting [Abstract]
Number of transmission interconnection facility subsidiaries | entity	2		2
Revenue
Electric operations	$ 341,062	$ 317,589	$ 897,486	$ 839,080
Other operations	20,186	21,282	61,067	59,627
Affiliate revenue	0	0	0	0
Electric customer credits	(2,992)	(372)	(24,276)	(1,045)
Operating revenue, net	358,256	338,499	934,277	897,662
Depreciation and amortization	43,763	42,228	128,076	124,630
Interest income	1,832	354	4,043	1,046
Interest charges	31,828	30,462	94,894	92,800
Federal and state income tax expense (benefit)	11,419	23,054	21,947	42,381
Net income (loss)	47,360	45,304	84,060	77,041
Additions to property, plant, and equipment			194,619	185,609
Equity investment in investee	18,172		18,172		$ 18,172
Goodwill	1,490,797		1,490,797		1,490,797	$ 1,490,000
Total segment assets	6,461,835		6,461,835		6,278,382
Operating Segments | CLECO POWER
Revenue
Electric operations	343,482	320,009	904,746	847,417
Other operations	20,186	20,768	61,066	58,083
Affiliate revenue	223	209	651	649
Electric customer credits	(2,992)	(372)	(24,276)	(1,045)
Operating revenue, net	360,899	340,614	942,187	905,104
Depreciation and amortization	41,687	40,049	121,796	118,280
Interest income	1,606	332	3,560	926
Interest charges	17,895	17,141	53,658	52,654
Federal and state income tax expense (benefit)	18,016	30,092	39,724	63,010
Net income (loss)	63,336	54,852	132,359	108,439
Additions to property, plant, and equipment			193,708	183,604
Equity investment in investee	18,172		18,172		18,172
Goodwill	1,490,797		1,490,797		1,490,797
Total segment assets	5,808,604		5,808,604		5,679,538
OTHER
Revenue
Electric operations	(2,420)	(2,420)	(7,260)	(8,337)
Other operations	0	514	1	1,544
Affiliate revenue	22,765	13,517	55,707	41,882
Electric customer credits	0	0	0	0
Operating revenue, net	20,345	11,611	48,448	35,089
Depreciation and amortization	2,076	2,179	6,281	6,351
Interest income	310	31	652	271
Interest charges	14,017	13,331	41,409	40,297
Federal and state income tax expense (benefit)	(6,597)	(7,038)	(17,777)	(20,629)
Net income (loss)	(15,975)	(9,548)	(48,299)	(31,398)
Additions to property, plant, and equipment			911	2,005
Equity investment in investee	0		0		0
Goodwill	0		0		0
Total segment assets	688,066		688,066		619,943
ELIMINATIONS
Revenue
Electric operations	0	0	0	0
Other operations	0	0	0
Affiliate revenue	(22,988)	(13,726)	(56,358)	(42,531)
Electric customer credits	0	0	0	0
Operating revenue, net	(22,988)	(13,726)	(56,358)	(42,531)
Depreciation and amortization	0	0	(1)	(1)
Interest income	(84)	(9)	(169)	(151)
Interest charges	(84)	(10)	(173)	(151)
Federal and state income tax expense (benefit)	0	0	0	0
Net income (loss)	(1)	$ 0	0	0
Additions to property, plant, and equipment			0	$ 0
Equity investment in investee	0		0		0
Goodwill	0		0		0
Total segment assets	$ (34,835)		$ (34,835)		$ (21,099)