Disclosures about Segments (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($) entity	Mar. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)
Segment Reporting [Abstract]
Number of transmission interconnection facility subsidiaries | entity	2
Revenue
Electric operations	$ 312,949	$ 262,211
Other operations	39,397	22,196
Affiliate revenue	0	0
Electric customer credits	(8,160)	(7,647)
Operating revenue, net	344,186	276,760
Depreciation and amortization	49,856	42,507
Interest income	1,491	783
Interest charges, net	33,999	31,157
Federal and state income tax expense (benefit)	5,986	2,862
Net income (loss)	20,557	10,861
Additions to property, plant, and equipment	83,679	64,133
Equity investment in investees	18,172		$ 18,172
Goodwill	1,490,797		1,490,797
Total segment assets	7,419,169		6,436,814
Operating Segments | CLECO POWER
Revenue
Electric operations	257,175	264,631
Other operations	19,430	22,195
Affiliate revenue	300	208
Electric customer credits	(8,160)	(7,647)
Operating revenue, net	268,745	279,387
Depreciation and amortization	42,377	40,388
Interest income	994	641
Interest charges, net	17,145	17,656
Federal and state income tax expense (benefit)	7,998	7,997
Net income (loss)	26,712	26,004
Additions to property, plant, and equipment	81,040	63,343
Equity investment in investees	18,172		18,172
Goodwill	1,490,797		1,490,797
Total segment assets	5,857,223		5,839,853
Operating Segments | CLECO CAJUN
Revenue
Electric operations	58,194
Other operations	19,965
Affiliate revenue	0
Electric customer credits	0
Operating revenue, net	78,159
Depreciation and amortization	5,410
Interest income	254
Interest charges, net	0
Federal and state income tax expense (benefit)	3,529
Net income (loss)	11,056
Additions to property, plant, and equipment	1,530
Equity investment in investees	0
Goodwill	0
Total segment assets	1,043,253
OTHER
Revenue
Electric operations	(2,420)	(2,420)
Other operations	2	1
Affiliate revenue	26,535	15,669
Electric customer credits	0	0
Operating revenue, net	24,117	13,250
Depreciation and amortization	2,069	2,119
Interest income	417	190
Interest charges, net	17,028	13,549
Federal and state income tax expense (benefit)	(5,540)	(5,135)
Net income (loss)	(17,210)	(15,142)
Additions to property, plant, and equipment	1,109	790
Equity investment in investees	0		0
Goodwill	0		0
Total segment assets	585,647		633,756
ELIMINATIONS
Revenue
Electric operations	0	0
Other operations	0	0
Affiliate revenue	(26,835)	(15,877)
Electric customer credits	0	0
Operating revenue, net	(26,835)	(15,877)
Depreciation and amortization	0	0
Interest income	(174)	(48)
Interest charges, net	(174)	(48)
Federal and state income tax expense (benefit)	(1)	0
Net income (loss)	(1)	(1)
Additions to property, plant, and equipment	0	$ 0
Equity investment in investees	0		0
Goodwill	0		0
Total segment assets	$ (66,954)		$ (36,795)