Fair Value Accounting, Carrying Value and Estimated Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Financial instruments not marked-to-market [Abstract]
Deferred debt issuance costs not included in the carrying value of long-term debt	$ 11,200	$ 11,700
Carrying Value
Financial instruments not marked-to-market [Abstract]
Long-term debt	2,743,987	2,768,149
Fair Value
Financial instruments not marked-to-market [Abstract]
Long-term debt	2,831,805	2,754,518
Cleco Power [Member]
Financial instruments not marked-to-market [Abstract]
Deferred debt issuance costs not included in the carrying value of long-term debt	8,600	9,400
Cleco Power [Member] | Carrying Value
Financial instruments not marked-to-market [Abstract]
Long-term debt	1,244,731	1,262,373
Cleco Power [Member] | Fair Value
Financial instruments not marked-to-market [Abstract]
Long-term debt	$ 1,428,761	$ 1,418,693