River Financial Corporation (Parent Company Only) Financial Information - Statements of Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Condensed Income Statements Captions [Line Items]
Total interest income	$ 71,798	$ 63,407
Interest expense - note payable	222	1,348
Subordinated debentures	1,381
Legal and other professional fees	841	762
Data processing expense	3,268	2,788
Other expenses	6,251	5,469
Applicable income tax benefit	7,163	4,595
Net income	25,036	17,090
River Financial Corporation
Condensed Income Statements Captions [Line Items]
Cash dividends from River Bank & Trust	3,000	7,130
Total interest income	3,000	7,130
Interest expense - note payable	222	1,348
Subordinated debentures	1,381
Legal and other professional fees	55	52
Data processing expense	4	(91)
Stockholders' meeting expense	14	11
Other expenses	371	249
Total expenses	2,047	1,569
Net income before tax benefit	953	5,561
Applicable income tax benefit	(494)	(417)
Net income before undistributed net income of River Bank & Trust	1,447	5,978
Equity in undistributed net income of River Bank & Trust	23,589	11,112
Net income	$ 25,036	$ 17,090