Condensed Consolidated Statements of Changes in Equity (USD $) In Thousands	Total	Public Service Company of New Mexico [Member]	Texas-New Mexico Power Company [Member]	Preferred Stock, Series A [Member]	Common Stock [Member]	Common Stock [Member] Public Service Company of New Mexico [Member]	Common Stock [Member] Texas-New Mexico Power Company [Member]	Additional Paid-in Capital [Member] Texas-New Mexico Power Company [Member]	AOCI [Member]	AOCI [Member] Public Service Company of New Mexico [Member]	AOCI [Member] Texas-New Mexico Power Company [Member]	Retained Earnings [Member]	Retained Earnings [Member] Public Service Company of New Mexico [Member]	Retained Earnings [Member] Texas-New Mexico Power Company [Member]	Total PNMR Common Stockholders' Equity [Member]	Total PNMR Common Stockholders' Equity [Member] Public Service Company of New Mexico [Member]	Non-controlling Interest in Valencia [Member]	Non-controlling Interest in Valencia [Member] Public Service Company of New Mexico [Member]	Common Stock [Member]	Common Stock [Member] Preferred Stock, Series A [Member]	Common Stock [Member]	Common Stock [Member] AOCI [Member]	Common Stock [Member] Retained Earnings [Member]	Common Stock [Member] Total PNMR Common Stockholders' Equity [Member]	Common Stock [Member] Non-controlling Interest in Valencia [Member]	Preferred Stock [Member]	Preferred Stock [Member] Preferred Stock, Series A [Member]	Preferred Stock [Member] Common Stock [Member]	Preferred Stock [Member] AOCI [Member]	Preferred Stock [Member] Retained Earnings [Member]	Preferred Stock [Member] Total PNMR Common Stockholders' Equity [Member]	Preferred Stock [Member] Non-controlling Interest in Valencia [Member]
Balance at Dec. 31, 2010	$ 1,721,919	$ 1,208,526		$ 100,000	$ 1,290,465	$ 1,018,776			$ (68,666)	$ (66,786)		$ 314,943	$ 171,359		$ 1,536,742	$ 1,123,349	$ 85,177	$ 85,177
Balance TNMP at Dec. 31, 2010	1,536,742	1,123,349	453,283				64	430,108			(1,485)			24,596
Proceeds from stock option exercise	2,570			0	2,570				0			0			2,570		0
Purchases to satisfy awards of common stock																			(5,288)	0	(5,288)	0	0	(5,288)	0	(73,510)	(100,000)	26,490	0	0	26,490	0
Stock based compensation expense	4,302			0	4,302				0			0			4,302		0
Valencia's transactions with its owner	(11,972)	(11,972)		0	0	0			0	0		0	0		0	0	(11,972)	(11,972)
Net earnings before subsidiary preferred stock dividends	75,526	51,634	17,134	0	0	0	0	0	0	0	0	64,762	40,870	17,134	64,762	40,870	10,764	10,764
Subsidiary preferred stock dividends	(396)			0	0				0			(396)			(396)		0
Total other comprehensive income (loss)	(4,247)	(5,180)	906	0	0	0	0	0	(4,247)	(5,180)	906	0	0	0	(4,247)	(5,180)	0	0
Dividends declared on preferred stock		(396)				0				0			(396)			(396)		0
Dividends declared on common stock	(33,695)	(8,212)	(7,066)	0	0	0	0	(7,066)	0	0	0	(33,695)	(8,212)	0	(33,695)	(8,212)	0	0
Balance TNMP at Sep. 30, 2011	1,591,240	1,150,431	464,257				64	423,042			(579)			41,730
Balance at Sep. 30, 2011	1,675,209	1,234,400		0	1,318,539	1,018,776			(72,913)	(71,966)		345,614	203,621		1,591,240	1,150,431	83,969	83,969
Balance at Jun. 30, 2011
Net earnings before subsidiary preferred stock dividends	47,905	42,572	8,868
Subsidiary preferred stock dividends	(132)
Total other comprehensive income (loss)	(2,222)	(3,498)	1,339
Balance TNMP at Sep. 30, 2011	1,591,240	1,150,431	464,257
Balance at Sep. 30, 2011	$ 1,675,209	$ 1,234,400