Quarterly Operating Results (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Operating revenues	$ 336,225	$ 400,374	$ 315,391	$ 310,961	$ 335,894	$ 417,433	$ 352,887	$ 332,868	$ 1,362,951	$ 1,439,082	$ 1,435,853
Operating income (loss)	63,584	108,071	64,822	41,508	(119,138)	121,505	72,414	49,569	277,985	124,350	299,697
Net earnings (loss)	28,423	58,556	30,952	13,965	(87,284)	64,855	35,655	17,852	131,896	31,078	130,909
Earnings Attributable to PNMR	$ 24,809	$ 54,418	$ 27,076	$ 10,546	$ (91,418)	$ 61,045	$ 31,673	$ 14,340	$ 116,849	$ 15,640	$ 116,254
Net Earnings Attributable to PNMR per Common Share:
Basic (dollars per share)	$ 0.32	$ 0.68	$ 0.34	$ 0.13	$ (1.15)	$ 0.77	$ 0.40	$ 0.18	$ 1.47	$ 0.20	$ 1.46
Diluted (dollars per share)	$ 0.31	$ 0.68	$ 0.34	$ 0.13	$ (1.15)	$ 0.76	$ 0.40	$ 0.18	$ 1.46	$ 0.20	$ 1.45
Regulatory disallowances and restructuring costs									$ 15,011	$ 167,471	$ 1,062
Public Service Company of New Mexico [Member]
Segment Reporting Information [Line Items]
Operating revenues	$ 255,685	$ 311,276	$ 233,346	$ 235,606	$ 260,368	$ 333,437	$ 275,450	$ 261,940	1,035,913	1,131,195	1,147,914
Operating income (loss)	42,976	80,057	41,760	23,297	(139,164)	93,710	47,179	31,655	188,090	33,380	212,713
Net earnings (loss)	19,594	44,990	19,793	7,561	(92,245)	53,056	25,363	13,502	91,938	(324)	101,453
Earnings Attributable to PNMR	16,112	40,984	16,049	4,274	(96,247)	49,378	21,513	10,122	77,419	(15,234)	87,326
Net Earnings Attributable to PNMR per Common Share:
Regulatory disallowances and restructuring costs									15,011	167,471	1,062
Public Service Company of New Mexico [Member] | Clean Air Act, SNCR [Member]
Net Earnings Attributable to PNMR per Common Share:
Regulatory disallowances and restructuring costs										21,600
Public Service Company of New Mexico [Member] | Clean Air Act, SNCR [Member] | San Juan Generating Station Units 2 and 3 [Member]
Net Earnings Attributable to PNMR per Common Share:
Regulatory disallowances and restructuring costs										127,600
Public Service Company of New Mexico [Member] | Increase in coal mine decommissioning liability [Member] | Clean Air Act, SNCR [Member] | San Juan Generating Station Units 2 and 3 [Member]
Net Earnings Attributable to PNMR per Common Share:
Regulatory disallowances and restructuring costs										165,700
Texas-New Mexico Power Company [Member]
Segment Reporting Information [Line Items]
Operating revenues									327,038	307,887	287,939
Operating revenues	80,540	89,098	82,045	75,355	75,526	83,996	77,437	70,928
Operating income (loss)	21,353	28,359	23,375	18,554	19,706	27,667	24,729	17,931	91,641	90,033	85,588
Earnings Attributable to PNMR	$ 9,855	$ 13,853	$ 10,508	$ 7,456	$ 8,715	$ 13,689	$ 11,865	$ 7,694	$ 41,672	$ 41,963	$ 37,807