Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Accumulated Deferred Federal and State Income Tax Assets and Liabilities [Line Items]
Depreciation and property basis differences	$ (865,807)	$ (862,263)
Net operating loss carryforward	109,819	120,955
NMTC	92,364	92,364
Fuel costs	(8,906)	(3,984)
Other comprehensive income	13,016	10,612
Regulated operations regulatory liability, net	47,060	34,836
Postretirement benefits	25,775	22,691
Merger fair value adjustments	(51,073)	(52,957)
Other	(23,624)	(19,312)
Accumulated deferred federal and state income taxes, net	(661,376)	(657,058)
CLECO POWER
Accumulated Deferred Federal and State Income Tax Assets and Liabilities [Line Items]
Depreciation and property basis differences	(725,034)	(705,423)
Net operating loss carryforward	35,442	2,714
Fuel costs	(7,072)	(5,608)
Other comprehensive income	8,274	7,510
Regulated operations regulatory liability, net	47,060	34,836
Postretirement benefits	11,951	10,044
Other	(5,219)	(1,907)
Accumulated deferred federal and state income taxes, net	$ (634,598)	$ (657,834)