Condensed Consolidated Statement Of Equity - USD ($) $ in Thousands	Total	Total National Health Investors, Inc. Stockholders’ Equity	Common Stock	Capital in Excess of Par Value	Retained Earnings	Cumulative Dividends	Noncontrolling Interests
Beginning balance (in shares) at Dec. 31, 2022			43,388,742
Beginning balance at Dec. 31, 2022	$ 1,280,081	$ 1,270,225	$ 434	$ 1,599,427	$ 2,331,190	$ (2,660,826)	$ 9,856
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Noncontrolling interest capital contribution	2,000						2,000
Distributions declared to noncontrolling interests	(273)						(273)
Net income, excluding loss attributable to redeemable noncontrolling interest	34,488	34,484			34,484		4
Equity issuance cost	(275)	(275)		(275)
Share-based compensation	2,105	2,105		2,105
Dividends declared, $0.90 per common share	(39,050)	(39,050)				(39,050)
Ending balance (in shares) at Mar. 31, 2023			43,388,742
Ending balance at Mar. 31, 2023	$ 1,279,076	1,267,489	$ 434	1,601,257	2,365,674	(2,699,876)	11,587
Beginning balance (in shares) at Dec. 31, 2023	43,409,841		43,409,841
Beginning balance at Dec. 31, 2023	$ 1,264,391	1,253,952	$ 434	1,603,757	2,466,844	(2,817,083)	10,439
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Distributions declared to noncontrolling interests	(205)						(205)
Net income, excluding loss attributable to redeemable noncontrolling interest	30,882	30,947			30,947		(65)
Grants of restricted stock (in shares)			15,000
Share-based compensation	2,155	2,155		2,155
Dividends declared, $0.90 per common share	$ (39,082)	(39,082)				(39,082)
Ending balance (in shares) at Mar. 31, 2024	43,409,841		43,424,841
Ending balance at Mar. 31, 2024	$ 1,258,141	$ 1,247,972	$ 434	$ 1,605,912	$ 2,497,791	$ (2,856,165)	$ 10,169