Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Amounts reclassified from accumulated AOCI
Total other comprehensive income (loss), net of tax	$ 261	$ (44)	$ 551	$ (2,175)
TOTAL AOCI
Amounts reclassified from accumulated AOCI
Total other comprehensive income (loss), net of tax			551
POSTRETIREMENT BENEFIT NET LOSS
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances, beginning of period	(2,631)	(631)	(2,921)	1,500
Other comprehensive loss before reclassifications
Postretirement benefits adjustment during the period		0		(2,065)
Amounts reclassified from accumulated AOCI
Amounts reclassified from accumulated AOCI	261	(44)	551	(110)
Total other comprehensive income (loss), net of tax	261	(44)	551	(2,175)
Balances, end of period	(2,370)	(675)	(2,370)	(675)
CLECO POWER
Amounts reclassified from accumulated AOCI
Total other comprehensive income (loss), net of tax	424	220	1,052	99
CLECO POWER | TOTAL AOCI
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances, beginning of period	(13,055)	(13,543)	(13,683)	(13,422)
Amounts reclassified from accumulated AOCI
Total other comprehensive income (loss), net of tax			1,052
Balances, end of period	(12,631)	(13,323)	(12,631)	(13,323)
CLECO POWER | POSTRETIREMENT BENEFIT NET LOSS
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances, beginning of period	(7,877)	(8,132)	(8,377)	(7,905)
Other comprehensive loss before reclassifications
Postretirement benefits adjustment during the period		0		(584)
Amounts reclassified from accumulated AOCI
Amounts reclassified from accumulated AOCI	312	167	812	524
Total other comprehensive income (loss), net of tax	312	167	812	(60)
Balances, end of period	(7,565)	(7,965)	(7,565)	(7,965)
CLECO POWER | NET LOSS ON CASH FLOW HEDGES
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances, beginning of period	(5,178)	(5,411)	(5,306)	(5,517)
Amounts reclassified from accumulated AOCI
Amounts reclassified from accumulated AOCI	112	53	240	159
Total other comprehensive income (loss), net of tax	112	53	240	159
Balances, end of period	$ (5,066)	$ (5,358)	$ (5,066)	$ (5,358)