Equity Method Investment - Summarized Financial Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Statement [Abstract]
Operating Revenues	$ 1,939,198	$ 2,249,555	$ 1,779,873
Balance Sheet Related Disclosures [Abstract]
Net property, plant, and equipment	589,834	372,988
Total assets	10,252,605	9,257,377	8,666,885
Total PNMR common stockholders’ equity	2,349,093	2,191,932
NMRD
Income Statement [Abstract]
Operating Revenues	13,629	12,505	12,738
Operating expenses	8,228	9,591	9,733
Net earnings	5,401	2,914	$ 3,005
Balance Sheet Related Disclosures [Abstract]
Current assets	2,589	8,357
Net property, plant, and equipment	235,791	169,440
Non-current assets	1,849	9,631
Total assets	240,229	187,428
Current liabilities	730	5,822
Non-current liabilities	358	366
Total PNMR common stockholders’ equity	$ 239,141	$ 181,240