Income Taxes - Accumulated Accrued Interest Receivable (Payable) Related to Income Taxes (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
PNMR [Member]
Income Taxes [Line Items]
Accumulated accrued interest receivable	$ 0	$ 3,236
Accumulated accrued interest payable	0	(1,120)
Public Service Company of New Mexico [Member]
Income Taxes [Line Items]
Accumulated accrued interest receivable	0	3,236
Accumulated accrued interest payable	0	(24)
Texas-New Mexico Power Company [Member]
Income Taxes [Line Items]
Accumulated accrued interest receivable	0	0
Accumulated accrued interest payable	$ 0	$ (120)