River Financial Corporation (Parent Company Only) Financial Information - Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Condensed Cash Flow Statements Captions [Line Items]
Net Income (Loss)	$ 26,739	$ 27,929
Adjustments to reconcile net income to net cash used for operating activities:
Amortization of debt issuance costs	73	75
(Increase) decrease in operating assets and (decrease) increase in operating liabilities:
Other assets	(4,712)	3,206
Net cash from operating activities	24,397	47,467
Cash Flows used for investing activities:
Net cash used for investing activities	(391,517)	(513,477)
Cash flow (used for) from financing activities:
Proceeds from issuance of line of credit	12,000
Repayment of line of credit	(12,000)
Proceeds from exercise of stock options	354	574
Proceeds from issuance of common stock	32,930
Purchase of treasury stock	(1,080)	(1,365)
Sale of treasury stock	839	1,134
Cash dividends	(3,208)	(2,918)
Net cash from financing activities	364,841	478,874
Net Change In Cash And Cash Equivalents	(2,279)	12,864
Cash and Cash Equivalents At Beginning Of Period	74,826
Cash and Cash Equivalents At End Of Period	72,547	74,826
River Financial Corporation
Condensed Cash Flow Statements Captions [Line Items]
Net Income (Loss)	26,739	27,929
Adjustments to reconcile net income to net cash used for operating activities:
Equity in undistributed net income of River Bank & Trust	(28,212)	(29,508)
Deferred income tax	2	27
Amortization of debt issuance costs	73	75
(Increase) decrease in operating assets and (decrease) increase in operating liabilities:
Other assets	23	(23)
Accrued expenses and other liabilities	539	6
Net cash from operating activities	(836)	(1,494)
Cash Flows used for investing activities:
Capital contribution to bank subsidiary	(27,218)	(1,500)
Net cash used for investing activities	(27,218)	(1,500)
Cash flow (used for) from financing activities:
Proceeds from issuance of line of credit	12,000
Repayment of line of credit	(12,000)
Proceeds from exercise of stock options	354	574
Proceeds from issuance of common stock	32,930
Purchase of treasury stock	(1,080)	(1,365)
Sale of treasury stock	839	1,134
Cash dividends	(3,208)	(2,918)
Net cash from financing activities	29,835	(2,575)
Net Change In Cash And Cash Equivalents	1,781	(5,569)
Cash and Cash Equivalents At Beginning Of Period	2,425	7,994
Cash and Cash Equivalents At End Of Period	$ 4,206	$ 2,425