Schedule II - Valuation and Qualifying Accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	$ 1,423	$ 1,751	$ 1,778
Charged to costs and expenses	3,267	2,849	3,367
Charged to other accounts	0	0	0
Write-offs and other	3,224	3,177	3,394
Balance at end of year	1,466	1,423	1,751
Public Service Company of New Mexico [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	1,423	1,751	1,778
Charged to costs and expenses	3,275	2,864	3,384
Charged to other accounts	0	0	0
Write-offs and other	3,232	3,192	3,411
Balance at end of year	1,466	1,423	1,751
Texas-New Mexico Power Company [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	0	0	0
Charged to costs and expenses	(8)	(15)	(17)
Charged to other accounts	0	0	0
Write-offs and other	(8)	(15)	(17)
Balance at end of year	$ 0	$ 0	$ 0

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Total of allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 09

-Article 12

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