Consolidated Statements of Changes in Common Stockholder's Equity - TNMP - USD ($) $ in Thousands	Total	Retained Earnings	TNMP	TNMP Common Stock	TNMP Paid-in Capital	TNMP Retained Earnings
Beginning Balance at Dec. 31, 2020			$ 825,678	$ 64	$ 685,166	$ 140,448
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings			63,879			63,879
Equity contribution from parent			52,000		52,000
Dividends declared on common stock	$ (84,333)	$ (84,333)	0
Ending Balance at Dec. 31, 2021			941,557	64	737,166	204,327
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings			92,267			92,267
Equity contribution from parent			68,000		68,000
Dividends declared on common stock	(150,855)	(150,855)
Ending Balance at Dec. 31, 2022	2,191,932		1,101,824	64	805,166	296,594
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings			94,937			94,937
Equity contribution from parent			40,900		40,900
Dividends declared on common stock	(129,586)	$ (129,586)
Ending Balance at Dec. 31, 2023	$ 2,349,093		$ 1,237,661	$ 64	$ 846,066	$ 391,531