Parent Company Information - Statements Of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Operating Activities:
Net income	$ 64,608	$ 36,971	$ 25,394
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities:
Gain on sale of securities, net	(1)	(112)	0
Amortization of debt issuance costs	14	0	0
Gain on sale by PWA	(14,486)	0	0
Unrealized (gain) on marketable equity securities	(169)	(465)	(120)
Stock-based compensation	1,734	913	937
Net Cash Provided (Used) by Operating Activities	139,337	(8,727)	38,775
Investing Activities:
Purchases of marketable equity securities	0	(1,964)	(2,297)
Proceeds from sales/calls/maturities of marketable equity securities	481	6,973	0
Net Cash Used by Investing Activities	(223,429)	(197,625)	(254,921)
Financing Activities:
Dividends paid to shareholders	(14,547)	(13,751)	(13,609)
Proceeds from the issuance of common stock	609	801	555
Proceeds from issuance of subordinated debentures	60,000	0	0
Payment of debt issuance costs	(1,400)	0	0
Repurchase of common stock	0	(789)	(9,044)
Net Cash Provided by Financing Activities	167,262	150,558	75,326
Net Change in Cash and Cash Equivalents	83,170	(55,794)	(140,820)
Cash and Cash Equivalents at Beginning of Year	62,736	118,530	259,350
Cash and Cash Equivalents at End of Year	145,906	62,736	118,530
Northrim Bancorp, Inc.
Operating Activities:
Net income	64,608	36,971	25,394
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities:
Gain on sale of securities, net	0	112	0
Amortization of debt issuance costs	14	0	0
Equity in undistributed earnings from subsidiaries	(46,956)	(37,252)	(26,892)
Gain on sale by PWA	(14,486)	0	0
Unrealized (gain) on marketable equity securities	(169)	(465)	(120)
Stock-based compensation	1,734	913	937
Changes in other assets and liabilities	(3,395)	(60)	(1,380)
Net Cash Provided (Used) by Operating Activities	1,350	219	(2,061)
Investing Activities:
Purchases of marketable equity securities	0	(1,964)	(2,297)
Proceeds from sales/calls/maturities of marketable equity securities	481	6,973	0
Investment in Northrim Bank, NISC & NST2	(35,928)	(6,157)	14,628
Net Cash Used by Investing Activities	(35,447)	(1,148)	12,331
Financing Activities:
Dividends paid to shareholders	(14,547)	(13,751)	(13,609)
Proceeds from the issuance of common stock	609	801	555
Proceeds from issuance of subordinated debentures	60,000	0	0
Payment of debt issuance costs	(1,400)	0	0
Repurchase of common stock	0	(789)	(9,044)
Net Cash Provided by Financing Activities	44,662	(13,739)	(22,098)
Net Change in Cash and Cash Equivalents	10,565	(14,668)	(11,828)
Cash and Cash Equivalents at Beginning of Year	4,387	19,055	30,883
Cash and Cash Equivalents at End of Year	$ 14,952	$ 4,387	$ 19,055