Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Amounts reclassified from accumulated other comprehensive income
Amortization of postretirement benefit net gain	$ 43	$ (126)
Postretirement benefits adjustment during the period		(2,065)
Total other comprehensive income (loss), net of tax	43	(2,191)
TOTAL AOCI
Accumulated other comprehensive loss [Roll Forward]
Balances, beginning of period	(2,921)	1,500
Amounts reclassified from accumulated other comprehensive income
Total other comprehensive income (loss), net of tax	43
Balances, end of period	(2,878)	(691)
POSTRETIREMENT BENEFIT NET LOSS
Accumulated other comprehensive loss [Roll Forward]
Balances, beginning of period	(2,921)	1,500
Amounts reclassified from accumulated other comprehensive income
Amortization of postretirement benefit net gain	43	(126)
Postretirement benefits adjustment during the period		(2,065)
Total other comprehensive income (loss), net of tax	43	(2,191)
Balances, end of period	(2,878)	(691)
NET LOSS ON CASH FLOW HEDGES
Accumulated other comprehensive loss [Roll Forward]
Balances, beginning of period	0	0
Amounts reclassified from accumulated other comprehensive income
Amortization of postretirement benefit net gain	0	0
Postretirement benefits adjustment during the period		0
Total other comprehensive income (loss), net of tax	0	0
Balances, end of period	0	0
Cleco Power
Amounts reclassified from accumulated other comprehensive income
Amortization of postretirement benefit net gain	233	164
Postretirement benefits adjustment during the period		(584)
Total other comprehensive income (loss), net of tax	297	(367)
Cleco Power | Interest Expense
Amounts reclassified from accumulated other comprehensive income
Amortization of postretirement benefit net gain	64	53
Cleco Power | TOTAL AOCI
Accumulated other comprehensive loss [Roll Forward]
Balances, beginning of period	(13,683)	(13,422)
Amounts reclassified from accumulated other comprehensive income
Total other comprehensive income (loss), net of tax	297
Balances, end of period	(13,386)	(13,789)
Cleco Power | POSTRETIREMENT BENEFIT NET LOSS
Accumulated other comprehensive loss [Roll Forward]
Balances, beginning of period	(8,377)	(7,905)
Amounts reclassified from accumulated other comprehensive income
Amortization of postretirement benefit net gain	233	164
Postretirement benefits adjustment during the period		(584)
Total other comprehensive income (loss), net of tax	233	(420)
Balances, end of period	(8,144)	(8,325)
Cleco Power | POSTRETIREMENT BENEFIT NET LOSS | Interest Expense
Amounts reclassified from accumulated other comprehensive income
Amortization of postretirement benefit net gain	0	0
Cleco Power | NET LOSS ON CASH FLOW HEDGES
Accumulated other comprehensive loss [Roll Forward]
Balances, beginning of period	(5,306)	(5,517)
Amounts reclassified from accumulated other comprehensive income
Amortization of postretirement benefit net gain	0	0
Postretirement benefits adjustment during the period		0
Total other comprehensive income (loss), net of tax	64	53
Balances, end of period	(5,242)	(5,464)
Cleco Power | NET LOSS ON CASH FLOW HEDGES | Interest Expense
Amounts reclassified from accumulated other comprehensive income
Amortization of postretirement benefit net gain	$ 64	$ 53