Parent Company Information (Balance Sheets) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Cash and cash equivalents	$ 141,313	$ 79,530	$ 66,033	$ 66,721
Investment securities available for sale	203,918	222,083
Other assets	34,889	34,238
Total assets		1,085,258
Junior subordinated debentures		18,558
Other liabilities		9,043
Total liabilities		959,823
Common stock		6,467
Additional paid-in capital		53,164
Retained earnings		65,469
Accumulated other comprehensive income		283
Total Northrim BanCorp shareholders’ equity		125,383
Total liabilities and shareholders’ equity		1,085,258
Northrim Bancorp, Inc. [Member]
Cash and cash equivalents	8,749	7,304	5,752	5,220
Investment securities available for sale	3,757	999
Due from NISC	414	513
Other assets	913	2,302
Total assets	154,818	144,182
Junior subordinated debentures	18,558	18,558
Other liabilities		241
Total liabilities	18,558	18,799
Common stock	6,512	6,467
Additional paid-in capital	53,638	53,164
Retained earnings	74,742	65,469
Accumulated other comprehensive income	1,368	283
Total Northrim BanCorp shareholders’ equity	136,260	125,383
Total liabilities and shareholders’ equity	154,818	144,182
Northrim Bank [Member] | Northrim Bancorp, Inc. [Member]
Investment in subsidiary	138,936	130,837
Northrim Investment Services Company [Member] | Northrim Bancorp, Inc. [Member]
Investment in subsidiary	1,491	1,669
Northrim Capital Trust 1 [Member] | Northrim Bancorp, Inc. [Member]
Investment in subsidiary	248	248
Northrim Statutory Trust 2 [Member] | Northrim Bancorp, Inc. [Member]
Investment in subsidiary	$ 310	$ 310