Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Accumulated Other Comprehensive Loss [Line Items]
Balances, beginning of period	$ 2,124,740	$ 2,096,357
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances, end of period	2,530,062	2,087,761
TOTAL AOCI
Accumulated Other Comprehensive Loss [Line Items]
Balances, beginning of period	1,786	(2,921)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances, end of period	1,651	(2,878)
POSTRETIREMENT BENEFIT NET GAIN (LOSS)
Accumulated Other Comprehensive Loss [Line Items]
Balances, beginning of period	1,786	(2,921)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Amounts reclassified from AOCI	(135)	43
Balances, end of period	1,651	(2,878)
CLECO POWER
Accumulated Other Comprehensive Loss [Line Items]
Balances, beginning of period	1,594,533	1,550,679
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances, end of period	1,621,465	1,548,980
CLECO POWER | TOTAL AOCI
Accumulated Other Comprehensive Loss [Line Items]
Balances, beginning of period	(13,182)	(13,683)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances, end of period	(12,962)	(13,386)
CLECO POWER | POSTRETIREMENT BENEFIT NET GAIN (LOSS)
Accumulated Other Comprehensive Loss [Line Items]
Balances, beginning of period	(7,060)	(8,377)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Amounts reclassified from AOCI	156	233
Balances, end of period	(6,904)	(8,144)
CLECO POWER | NET LOSS ON CASH FLOW HEDGES
Accumulated Other Comprehensive Loss [Line Items]
Balances, beginning of period	(6,122)	(5,306)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Amounts reclassified from AOCI	64	64
Balances, end of period	$ (6,058)	$ (5,242)