Schedule II - Valuation and Qualifying Accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended														0 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009		Dec. 31, 2011 Public Service Company of New Mexico [Member]	Dec. 31, 2010 Public Service Company of New Mexico [Member]		Dec. 31, 2009 Public Service Company of New Mexico [Member]		Dec. 31, 2011 Texas-New Mexico Power Company [Member]	Dec. 31, 2010 Texas-New Mexico Power Company [Member]	Dec. 31, 2009 Texas-New Mexico Power Company [Member]	Nov. 01, 2011 First Choice [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of year	$ 11,178		$ 12,783	[1]	$ 21,466	[1]	$ 1,483	$ 1,483	[1]	$ 1,345	[1]	$ 0	$ 0	$ 0
Charged to costs and expenses	24,116		27,566		43,937	[1]	3,736	2,600		2,534	[1]	33	22	238
Charged to other accounts	0		0		0	[1]	0	0		0	[1]	0	0	0
Write-offs and other	33,516	[2]	29,171		52,620	[1]	3,441	2,600		2,396	[1]	33	22	238
Balance at end of year	1,778		11,178		12,783	[1]	1,778	1,483		1,483	[1]	0	0	0
Valuation Allowances and Reserves, reduction due to sale of business divestiture															$ 11,818

[1] Totals reflect continuing operations.

[2] Includes reduction of $11,818 due to the sale of First Choice on November 1, 2011.