Consolidated Statements of Changes in Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	AOCI [Member]	Retained Earnings [Member]	Total Stockholders' Equity [Member]	Non-controlling Interest in Valencia [Member]	Public Service Company of New Mexico [Member]	Public Service Company of New Mexico [Member] Common Stock [Member]	Public Service Company of New Mexico [Member] AOCI [Member]	Public Service Company of New Mexico [Member] Retained Earnings [Member]	Public Service Company of New Mexico [Member] Total Stockholders' Equity [Member]	Public Service Company of New Mexico [Member] Non-controlling Interest in Valencia [Member]	Texas-New Mexico Power Company [Member]	Texas-New Mexico Power Company [Member] Common Stock [Member]	Texas-New Mexico Power Company [Member] Paid-in Capital [Member]	Texas-New Mexico Power Company [Member] AOCI [Member]	Texas-New Mexico Power Company [Member] Retained Earnings [Member]
Balance at Dec. 31, 2012	$ 1,689,030	$ 1,182,819	$ (81,630)	$ 506,998	$ 1,608,187	$ 80,843	$ 1,334,906	$ 1,061,776	$ (81,414)	$ 273,701	$ 1,254,063	$ 80,843
Balance TNMP at Dec. 31, 2012													$ 463,814	$ 64	$ 390,366	$ (216)	$ 73,600
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Proceeds from stock option exercise	4,618	4,618			4,618
Purchases to satisfy awards of common stock	(13,807)	13,807			(13,807)
Net Earnings	100,507						88,155						29,090				29,090
Excess tax (shortfall) from stock-based payment arrangements	(581)	(581)			(581)
Stock based compensation expense	5,320	5,320			5,320
Valencia’s transactions with its owner	(18,335)			0	0	18,335	(18,335)		0	0	0
Net earnings	115,556			101,035	101,035	14,521	102,676		0	88,155	88,155	14,521
Preferred Stock Dividends Requirements	(528)			(528)	(528)		(528)		0	(528)	(528)
Total other comprehensive income	23,490		23,490	0	23,490		23,537		23,537	0	23,537		(47)			(47)
Equity contribution from parent							0						13,800		13,800
Dividends declared on common stock	(54,165)			(54,165)	(54,165)		(155,028)		0	(155,028)	(155,028)		(3,726)				(3,726)
Balance at Dec. 31, 2013	1,750,598	1,178,369	(58,140)	553,340	1,673,569	77,029	1,287,228	1,061,776	(57,877)	206,300	1,210,199	77,029
Balance TNMP at Dec. 31, 2013													502,931	64	404,166	(263)	98,964
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Proceeds from stock option exercise	6,999	6,999			6,999
Purchases to satisfy awards of common stock	(17,319)	17,319			(17,319)
Net Earnings	116,254						87,326						37,807				37,807
Excess tax (shortfall) from stock-based payment arrangements	(135)	(135)			(135)
Stock based compensation expense	5,931	5,931			5,931
Valencia’s transactions with its owner	(17,610)				0	17,610	(17,610)		0	0	0
Net earnings	130,909		0	116,782	116,782	14,127	101,453		0	87,326	87,326	14,127
Preferred Stock Dividends Requirements	(528)		0	(528)	(528)	0	(528)		0	(528)	(528)
Total other comprehensive income	(3,615)		(3,615)	0	(3,615)	0	(3,878)		(3,878)	0	(3,878)		263			$ 263
Equity contribution from parent							0						0
Dividends declared on common stock	(60,138)		0	(60,138)	(60,138)	0	(30,263)		0	(30,263)	(30,263)		(16,336)				(16,336)
Balance at Dec. 31, 2014	1,795,092	1,173,845	(61,755)	609,456	1,721,546	73,546	1,336,402	1,061,776	(61,755)	262,835	1,262,856	73,546
Balance TNMP at Dec. 31, 2014	1,721,546						1,262,856						524,665	64	404,166		120,435
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Proceeds from stock option exercise	5,619	5,619			5,619
Purchases to satisfy awards of common stock	(17,720)	17,720			(17,720)
Net Earnings	15,640						(15,234)						41,963				41,963
Excess tax (shortfall) from stock-based payment arrangements	(142)	(142)			(142)
Stock based compensation expense	4,863	4,863			4,863
Valencia’s transactions with its owner	(17,049)	0			0	17,049	(17,049)
Net earnings	31,078	0		16,168	16,168	14,910	(324)			(15,234)	(15,234)	14,910
Preferred Stock Dividends Requirements	(528)	0		(528)	(528)		(528)			(528)	(528)
Total other comprehensive income	(9,677)	0	(9,677)	0	(9,677)		(9,721)		(9,721)		(9,721)		0
Equity contribution from parent							175,000	175,000			175,000		0
Dividends declared on common stock	(65,316)	0	0	(65,316)	(65,316)		(94,440)			(94,440)	(94,440)		(33,248)				(33,248)
Balance at Dec. 31, 2015	1,726,220	$ 1,166,465	$ (71,432)	$ 559,780	$ 1,654,813	$ 71,407	1,389,340	$ 1,236,776	$ (71,476)	$ 152,633	$ 1,317,933	$ 71,407
Balance TNMP at Dec. 31, 2015	$ 1,654,813						$ 1,317,933						$ 533,380	$ 64	$ 404,166		$ 129,150