Fair Value Accounting - Fair Value of Financial Assets and Liabilities Measured On A Recurring Basis (Details) - Measured On A Recurring Basis - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Asset description
Institutional money market funds	$ 137,829	$ 133,722
FTRs	17,080	23,355
Total assets	154,909	157,077
Liability description
Total liabilities	5,185	468
FTRs
Liability description
FTRs and other commodity derivatives	2,415	468
Other commodity derivatives
Liability description
FTRs and other commodity derivatives	2,770	0
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
Total liabilities	0	0
QUOTED PRICES IN ACTIVE MARKETS FOR IDENTICAL ASSETS (LEVEL 1) | FTRs
Liability description
FTRs and other commodity derivatives	0	0
QUOTED PRICES IN ACTIVE MARKETS FOR IDENTICAL ASSETS (LEVEL 1) | Other commodity derivatives
Liability description
FTRs and other commodity derivatives	0	0
SIGNIFICANT OTHER OBSERVABLE INPUTS (LEVEL 2)
Asset description
Institutional money market funds	137,829	133,722
FTRs	0	0
Total assets	137,829	133,722
Liability description
Total liabilities	2,770	0
SIGNIFICANT OTHER OBSERVABLE INPUTS (LEVEL 2) | FTRs
Liability description
FTRs and other commodity derivatives	0	0
SIGNIFICANT OTHER OBSERVABLE INPUTS (LEVEL 2) | Other commodity derivatives
Liability description
FTRs and other commodity derivatives	2,770	0
SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3)
Asset description
Institutional money market funds	0	0
FTRs	17,080	23,355
Total assets	17,080	23,355
Liability description
FTRs and other commodity derivatives	2,415	468
Total liabilities	2,415	468
SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3) | FTRs
Liability description
FTRs and other commodity derivatives	2,415	468
SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3) | Other commodity derivatives
Liability description
FTRs and other commodity derivatives	0	0
CLECO POWER
Asset description
Institutional money market funds	50,493	55,900
FTRs	14,742	23,355
Total assets	65,235	79,255
Liability description
FTRs and other commodity derivatives	832	468
Total liabilities	832	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 and other commodity derivatives	0	0
Total liabilities	0	0
CLECO POWER | SIGNIFICANT OTHER OBSERVABLE INPUTS (LEVEL 2)
Asset description
Institutional money market funds	50,493	55,900
FTRs	0	0
Total assets	50,493	55,900
Liability description
FTRs and other commodity derivatives	0	0
Total liabilities	0	0
CLECO POWER | SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3)
Asset description
Institutional money market funds	0	0
FTRs	14,742	23,355
Total assets	14,742	23,355
Liability description
FTRs and other commodity derivatives	832	468
Total liabilities	$ 832	$ 468