Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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Name:	us-gaap_Goodwill
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Goodwill (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Apr. 01, 2020	Dec. 31, 2019
Schedule of Goodwill and Other Intangible Assets [Line Items]
Goodwill	$ 278,297	$ 278,297		$ 278,297
Texas-New Mexico Power Company
Schedule of Goodwill and Other Intangible Assets [Line Items]
Goodwill	$ 226,665	$ 226,665	$ 226,700
Percentage of fair value in excess of carrying amount			38.00%