Parent Company Information - Statements Of Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income
Interest income	$ 131,951	$ 100,328	$ 84,606
Gain on sale of marketable equity securities, net	0	0	67
Unrealized gain (loss) on marketable equity securities	120	(1,119)	(101)
Other income	26,375	34,077	52,263
Expense
Interest expense	28,695	5,213	3,779
Income Before Provision for Income Taxes	31,608	38,494	47,993
Benefit from income taxes	6,214	7,753	10,476
Net income	25,394	30,741	37,517
Northrim Bancorp, Inc.
Income
Interest income	1,258	698	551
Gain on sale of marketable equity securities, net	0	0	67
Unrealized gain (loss) on marketable equity securities	120	(1,119)	(101)
Other income	0	0	151
Total Income	28,227	32,552	39,359
Expense
Interest expense	400	389	382
Administrative and other expenses	3,357	2,830	2,754
Total Expense	3,757	3,219	3,136
Income Before Provision for Income Taxes	24,470	29,333	36,223
Benefit from income taxes	(924)	(1,408)	(1,294)
Net income	25,394	30,741	37,517
Northrim Bancorp, Inc. | Northrim Bank
Income
Equity in undistributed earnings from subsidiaries	26,871	32,853	38,625
Northrim Bancorp, Inc. | Northrim Investment Services Company
Income
Equity in undistributed earnings from subsidiaries	$ (22)	$ 120	$ 66