Income Taxes, Current and Deferred Income Tax Expense (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Apr. 12, 2016	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Items charged or credited directly to shareholders' equity
Increase (Decrease) in Deferred Income Taxes			$ 46,300
Predecessor [Member]
Current and deferred income tax expense [Abstract]
Current federal income tax (benefit) expense	$ 1,373				$ 1,284
Deferred Federal Income Tax Expense (Benefit)	5,297				76,219
Amortization of accumulated deferred investment tax credits	(124)				(916)
Total federal income tax (benefit) expense	6,546				76,587
Current state income tax (benefit) expense	0				3,233
Deferred state income tax expense (benefit)	(3,078)				(2,116)
Total state income tax expense (benefit)	(3,078)				1,117
Total taxes	3,468				77,704
Items charged or credited directly to shareholders' equity
Income Tax Effects Allocated Directly to Equity	(322)				3,802
Total federal and state income tax expense	3,146				81,506
Predecessor [Member] | Federal [Member]
Items charged or credited directly to shareholders' equity
Income Tax Effects Allocated Directly to Equity	(277)				3,274
Predecessor [Member] | State [Member]
Items charged or credited directly to shareholders' equity
Income Tax Effects Allocated Directly to Equity	$ (45)				528
Successor [Member]
Current and deferred income tax expense [Abstract]
Current federal income tax (benefit) expense		$ (1,062)	46,520
Deferred Federal Income Tax Expense (Benefit)		(16,715)	(47,329)
Amortization of accumulated deferred investment tax credits		(371)	(662)
Total federal income tax (benefit) expense		(18,148)	(1,471)
Current state income tax (benefit) expense		(337)	3,187
Deferred state income tax expense (benefit)		(4,337)	5,363
Total state income tax expense (benefit)		(4,674)	8,550
Total taxes		(22,822)	7,079
Items charged or credited directly to shareholders' equity
Income Tax Effects Allocated Directly to Equity		17,034	(452)
Total federal and state income tax expense		(5,788)	6,627
Successor [Member] | Federal [Member]
Items charged or credited directly to shareholders' equity
Income Tax Effects Allocated Directly to Equity		14,593	(659)
Successor [Member] | State [Member]
Items charged or credited directly to shareholders' equity
Income Tax Effects Allocated Directly to Equity		$ 2,441	207
Cleco Power [Member]
Current and deferred income tax expense [Abstract]
Current federal income tax (benefit) expense			87,433	$ (1,211)	33,138
Deferred Federal Income Tax Expense (Benefit)			(29,190)	22,647	45,572
Amortization of accumulated deferred investment tax credits			(662)	(494)	(916)
Total federal income tax (benefit) expense			57,581	20,942	77,794
Current state income tax (benefit) expense			14,751	(418)	3,397
Deferred state income tax expense (benefit)			(5,001)	(2,155)	(1,897)
Total state income tax expense (benefit)			9,750	(2,573)	1,500
Total taxes			67,331	18,369	79,294
Items charged or credited directly to shareholders' equity
Income Tax Effects Allocated Directly to Equity			(2,333)	2,295	123
Total federal and state income tax expense			64,998	20,664	79,417
Increase (Decrease) in Deferred Income Taxes			14,300
Cleco Power [Member] | Federal [Member]
Items charged or credited directly to shareholders' equity
Income Tax Effects Allocated Directly to Equity			(2,573)	1,976	106
Cleco Power [Member] | State [Member]
Items charged or credited directly to shareholders' equity
Income Tax Effects Allocated Directly to Equity			$ 240	$ 319	$ 17