Parent Company Information - Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
ASSETS
Marketable equity securities	$ 7,945	$ 7,265
Taxes receivable	1,429	8,188
Other assets	58,076	56,504
Total assets	1,643,996	1,502,988	$ 1,518,596
LIABILITIES
Junior subordinated debentures	10,310	10,310
Other liabilities	31,098	17,124
Total liabilities	1,436,879	1,297,041
SHAREHOLDERS' EQUITY
Common stock	6,559	6,883
Additional paid-in capital	50,512	62,132
Retained earnings	149,615	137,452
Accumulated other comprehensive income (loss), net of tax	431	(520)
Total liabilities and shareholders' equity	1,643,996	1,502,988
Northrim Bancorp, Inc.
ASSETS
Cash and cash equivalents	25,294	18,314
Marketable equity securities	7,945	7,265
Taxes receivable	0	6,914
Other assets	6	800
Total assets	218,370	216,885
LIABILITIES
Junior subordinated debentures	10,310	10,310
Other liabilities	943	628
Total liabilities	11,253	10,938
SHAREHOLDERS' EQUITY
Common stock	6,559	6,883
Additional paid-in capital	50,512	62,132
Retained earnings	149,615	137,452
Accumulated other comprehensive income (loss), net of tax	431	(520)
Total Northrim BanCorp, Inc. shareholders' equity	207,117	205,947
Total liabilities and shareholders' equity	218,370	216,885
Northrim Bancorp, Inc. | Northrim Bank
ASSETS
Investment in subsidiary	183,285	181,781
Northrim Bancorp, Inc. | Northrim Investment Services Company
ASSETS
Investment in subsidiary	1,530	1,501
Northrim Bancorp, Inc. | Northrim Statutory Trust 2
ASSETS
Investment in subsidiary	$ 310	$ 310