Pension Plan and Employee Benefits - Current and Non-current Portions of the Other Benefits Liability (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Non-current	$ 243,740	$ 242,135
OTHER BENEFITS
Defined Benefit Plan Disclosure [Line Items]
Current	4,061	4,061
Non-current	38,270	39,142
SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Current	4,471	4,471
Non-current	79,487	79,868
CLECO POWER
Defined Benefit Plan Disclosure [Line Items]
Non-current	172,220	173,747
CLECO POWER | OTHER BENEFITS
Defined Benefit Plan Disclosure [Line Items]
Current	3,525	3,525
Non-current	33,302	34,033
CLECO POWER | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Current	929	929
Non-current	$ 12,934	$ 16,589