Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances, beginning of period	$ 2,530,062	$ 2,087,761	$ 2,124,740	$ 2,096,357
Amounts reclassified from accumulated AOCI
Balances, end of period	2,574,661	2,093,447	2,574,661	2,093,447
TOTAL AOCI
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances, beginning of period	1,651	(2,878)	1,786	(2,921)
Amounts reclassified from accumulated AOCI
Balances, end of period	1,504	(2,631)	1,504	(2,631)
POSTRETIREMENT BENEFIT NET LOSS
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances, beginning of period	1,651	(2,878)	1,786	(2,921)
Amounts reclassified from accumulated AOCI
Amounts reclassified from AOCI	(147)	247	(282)	290
Balances, end of period	1,504	(2,631)	1,504	(2,631)
CLECO POWER
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances, beginning of period	1,621,465	1,548,980	1,594,533	1,550,679
Amounts reclassified from accumulated AOCI
Balances, end of period	1,671,014	1,549,331	1,671,014	1,549,331
CLECO POWER | TOTAL AOCI
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances, beginning of period	(12,962)	(13,386)	(13,182)	(13,683)
Amounts reclassified from accumulated AOCI
Balances, end of period	(12,769)	(13,055)	(12,769)	(13,055)
CLECO POWER | POSTRETIREMENT BENEFIT NET LOSS
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances, beginning of period	(6,904)	(8,144)	(7,060)	(8,377)
Amounts reclassified from accumulated AOCI
Amounts reclassified from AOCI	129	267	285	500
Balances, end of period	(6,775)	(7,877)	(6,775)	(7,877)
CLECO POWER | NET LOSS ON CASH FLOW HEDGES
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances, beginning of period	(6,058)	(5,242)	(6,122)	(5,306)
Amounts reclassified from accumulated AOCI
Amounts reclassified from AOCI	64	64	128	128
Balances, end of period	$ (5,994)	$ (5,178)	$ (5,994)	$ (5,178)