Stock-Based Compensation - Excess Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Public Service Company of New Mexico
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Excess tax benefits	$ 564	$ 279	$ 559
Texas-New Mexico Power Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Excess tax benefits	224	112	236
PNMR
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Excess tax benefits	$ 788	$ 391	$ 795