Pension Plan and Employee Benefits, SERP (Details) - SERP Benefits [Member] - USD ($) $ in Thousands		3 Months Ended			6 Months Ended	9 Months Ended
	Mar. 30, 2017	Sep. 30, 2017	Sep. 30, 2016	Apr. 12, 2016	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Mar. 29, 2017	Dec. 31, 2016	Aug. 31, 2016	Apr. 13, 2016
Components of periodic benefit costs [Abstract]
Service cost		$ 123	$ 213
Interest cost		810	839
Prior period service (credit) cost		57	9
Net loss (gain)		536	511
Curtailment charge				$ 3,600
Special/contractual termination benefits	$ 300
Total benefit cost		1,412	1,554
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement				$ 3,200
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate (in hundredths)	4.08%			4.60%				4.22%		3.47%	4.15%
Current portion of SERP liability		4,431				$ 4,431			$ 4,308
Noncurrent portion of SERP liability		76,870				76,870			73,738
Successor
Components of periodic benefit costs [Abstract]
Service cost					$ 277	370
Interest cost					1,543	2,430
Prior period service (credit) cost					42	124
Net loss (gain)					1,120	1,560
Net periodic benefit cost					2,898	4,236
Curtailment charge					0	0
Special/contractual termination benefits					0	315
Total benefit cost					$ 2,898	4,551
Predecessor
Components of periodic benefit costs [Abstract]
Service cost				$ 702
Interest cost				900
Prior period service (credit) cost				(17)
Net loss (gain)				574
Net periodic benefit cost				2,193
Curtailment charge				3,602
Special/contractual termination benefits				3,222
Total benefit cost				$ 9,017
Cleco Power [Member]
Components of periodic benefit costs [Abstract]
Total benefit cost		300	$ 300			900	$ 1,100
Current portion of SERP liability		939				939			885
Noncurrent portion of SERP liability		$ 15,999				$ 15,999			$ 15,145