Fair Value Accounting - Fair Value of Financial Assets and Liabilities Measured On A Recurring Basis (Details) - Measured On A Recurring Basis - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Asset description
Institutional money market funds	$ 109,848	$ 133,722
FTRs	9,171	23,355
Total assets	119,019	157,077
Liability description
FTRs	1,361	468
Total liabilities	1,361	468
QUOTED PRICES IN ACTIVE MARKETS FOR IDENTICAL ASSETS (LEVEL 1)
Asset description
Institutional money market funds	0	0
FTRs	0	0
Total assets	0	0
Liability description
FTRs	0	0
Total liabilities	0	0
SIGNIFICANT OTHER OBSERVABLE INPUTS (LEVEL 2)
Asset description
Institutional money market funds	109,848	133,722
FTRs	0	0
Total assets	109,848	133,722
Liability description
FTRs	0	0
Total liabilities	0	0
SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3)
Asset description
Institutional money market funds	0	0
FTRs	9,171	23,355
Total assets	9,171	23,355
Liability description
FTRs	1,361	468
Total liabilities	1,361	468
CLECO POWER
Asset description
Institutional money market funds	43,918	55,900
FTRs	5,684	23,355
Total assets	49,602	79,255
Liability description
FTRs	872	468
Total liabilities	872	468
CLECO POWER | QUOTED PRICES IN ACTIVE MARKETS FOR IDENTICAL ASSETS (LEVEL 1)
Asset description
Institutional money market funds	0	0
FTRs	0	0
Total assets	0	0
Liability description
FTRs	0	0
Total liabilities	0	0
CLECO POWER | SIGNIFICANT OTHER OBSERVABLE INPUTS (LEVEL 2)
Asset description
Institutional money market funds	43,918	55,900
FTRs	0	0
Total assets	43,918	55,900
Liability description
FTRs	0	0
Total liabilities	0	0
CLECO POWER | SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3)
Asset description
Institutional money market funds	0	0
FTRs	5,684	23,355
Total assets	5,684	23,355
Liability description
FTRs	872	468
Total liabilities	$ 872	$ 468