Income Taxes Summary of Income Tax Contingencies (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	$ 15,031	$ 19,889	$ 19,198
Additions based on tax positions			(54)
Additions based on tax positions	1,214	623
Additions (reductions) for tax positions of prior years	(9,790)	(5,481)
Additions (reductions) for tax positions of prior years			(745)
Settlement payments	0	0	0
Ending balance	6,455	15,031	19,889
Public Service Company of New Mexico [Member]
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	12,228	11,073	10,382
Additions based on tax positions			(54)
Additions based on tax positions	1,214	623
Additions (reductions) for tax positions of prior years	(9,790)
Additions (reductions) for tax positions of prior years		532	(745)
Settlement payments	0	0	0
Ending balance	3,652	12,228	11,073
Unrecognized tax benefits that would impact effective tax rate	3,100
Texas-New Mexico Power Company [Member]
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	0	6,796	6,796
Additions based on tax positions			0
Additions based on tax positions	0	0
Additions (reductions) for tax positions of prior years	0	(6,796)
Additions (reductions) for tax positions of prior years			0
Settlement payments	0	0	0
Ending balance	0	$ 0	$ 6,796
PNMR [Member]
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits that would impact effective tax rate	$ 5,900