Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Accumulated Deferred Federal and State Income Tax Assets and Liabilities [Line Items]
Depreciation and property basis differences	$ (664,996)	$ (596,824)
Net operating loss carryforward	0	12,873
NMTC	86,673	96,917
Fuel costs	(8,339)	(3,283)
Other comprehensive income	640
Other comprehensive income		(490)
Regulated operations regulatory liability, net	39,808
Regulated operations regulatory liability, net		(54,471)
Postretirement benefits	19,580	23,642
Merger fair value adjustments	(56,725)	(58,251)
Other	(24,671)	(34,925)
Accumulated deferred federal and state income taxes, net	(608,030)	(614,812)
CLECO POWER
Accumulated Deferred Federal and State Income Tax Assets and Liabilities [Line Items]
Depreciation and property basis differences	(666,224)	(597,838)
Net operating loss carryforward	0	470
Fuel costs	(8,339)	(3,282)
Other comprehensive income	4,192	5,250
Regulated operations regulatory liability, net	39,808
Regulated operations regulatory liability, net		(54,471)
Postretirement benefits	11,081	6,266
Other	(11,283)	(12,757)
Accumulated deferred federal and state income taxes, net	$ (630,765)	$ (656,362)