Parent Company Information - Statements Of Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income
Interest income	$ 153,919	$ 131,951	$ 100,328
Gain on sale of marketable equity securities, net	112	0	0
Unrealized gain (loss) on marketable equity securities	465	120	(1,119)
Total Income	195,960	158,326	134,405
Expense
Interest expense	40,736	28,695	5,213
Income Before Provision for Income Taxes	46,994	31,608	38,494
Benefit from income taxes	10,023	6,214	7,753
Net income	36,971	25,394	30,741
Northrim Bancorp, Inc.
Income
Interest income	1,203	1,258	698
Gain on sale of marketable equity securities, net	112	0	0
Unrealized gain (loss) on marketable equity securities	465	120	(1,119)
Total Income	39,197	28,227	32,552
Expense
Interest expense	403	400	389
Administrative and other expenses	3,381	3,357	2,830
Total Expense	3,784	3,757	3,219
Income Before Provision for Income Taxes	35,413	24,470	29,333
Benefit from income taxes	(1,558)	(924)	(1,408)
Net income	36,971	25,394	30,741
Northrim Bancorp, Inc. | Northrim Bank
Income
Equity in undistributed earnings from subsidiaries	37,334	26,871	32,853
Northrim Bancorp, Inc. | Northrim Investment Services Company
Income
Equity in undistributed earnings from subsidiaries	$ 83	$ (22)	$ 120