Parent Company Information - Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
ASSETS
Marketable equity securities	$ 8,420	$ 9,052
Taxes receivable	1,994	4,083
Other assets	54,361	68,488
Total assets	2,724,719	2,121,798	$ 1,643,996
LIABILITIES
Junior subordinated debentures	10,310	10,310
Other liabilities	29,488	37,737
Total liabilities	2,486,902	1,900,223
SHAREHOLDERS' EQUITY
Common stock	6,015	6,251
Additional paid-in capital	31,162	41,808
Retained earnings	204,046	173,498
Accumulated other comprehensive (loss) income	(3,406)	18
Total shareholders' equity	237,817	221,575	$ 207,117	$ 205,947
Total liabilities and shareholders' equity	2,724,719	2,121,798
Northrim Bancorp, Inc.
ASSETS
Cash and cash equivalents	35,546	24,742
Marketable equity securities	8,420	9,052
Taxes receivable	603	1,973
Other assets	358	497
Total assets	249,392	234,048
LIABILITIES
Junior subordinated debentures	10,310	10,310
Other liabilities	1,265	2,163
Total liabilities	11,575	12,473
SHAREHOLDERS' EQUITY
Common stock	6,015	6,251
Additional paid-in capital	31,162	41,808
Retained earnings	204,046	173,498
Accumulated other comprehensive (loss) income	(3,406)	18
Total shareholders' equity	237,817	221,575
Total liabilities and shareholders' equity	249,392	234,048
Northrim Bancorp, Inc. | Northrim Bank
ASSETS
Investment in subsidiary	202,819	196,002
Northrim Bancorp, Inc. | Northrim Investment Services Company
ASSETS
Investment in subsidiary	1,336	1,472
Northrim Bancorp, Inc. | Northrim Statutory Trust 2
ASSETS
Investment in subsidiary	$ 310	$ 310