Parent Company Information - Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
ASSETS
Marketable equity securities	$ 13,153	$ 10,740
Taxes receivable	1,726	1,749
Other assets	71,789	68,846
Total assets	2,807,497	2,674,318	$ 2,724,719
LIABILITIES
Junior subordinated debentures	10,310	10,310
Other liabilities	54,647	34,208
Total liabilities	2,572,779	2,455,689
SHAREHOLDERS' EQUITY
Common stock	5,513	5,701
Additional paid-in capital	9,605	17,784
Retained earnings	236,037	224,225
Accumulated other comprehensive (loss) income	(16,437)	(29,081)
Total shareholders' equity	234,718	218,629	$ 237,817	$ 221,575
Total liabilities and shareholders' equity	2,807,497	2,674,318
Northrim Bancorp, Inc.
ASSETS
Cash and cash equivalents	19,055	30,883
Marketable equity securities	13,153	10,740
Taxes receivable	1,212	463
Other assets	2,152	1,435
Total assets	245,484	229,224
LIABILITIES
Junior subordinated debentures	10,310	10,310
Other liabilities	456	285
Total liabilities	10,766	10,595
SHAREHOLDERS' EQUITY
Common stock	5,513	5,701
Additional paid-in capital	9,605	17,784
Retained earnings	236,037	224,225
Accumulated other comprehensive (loss) income	(16,437)	(29,081)
Total shareholders' equity	234,718	218,629
Total liabilities and shareholders' equity	245,484	229,224
Northrim Bancorp, Inc. | Northrim Bank
ASSETS
Investment in subsidiary	208,435	184,148
Northrim Bancorp, Inc. | Northrim Investment Services Company
ASSETS
Investment in subsidiary	1,167	1,245
Northrim Bancorp, Inc. | Northrim Statutory Trust 2
ASSETS
Investment in subsidiary	$ 310	$ 310