Parent Company Information (Statements Of Income) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Interest income	$ 11,349	$ 11,204	$ 11,123	$ 11,052	$ 11,540	$ 11,230	$ 11,486	$ 11,652	$ 44,728	$ 45,908	$ 49,698
Other income	4,343	4,157	3,725	3,207	3,880	3,362	3,070	2,778	15,432	13,090	12,377
Interest expense	569	611	627	698	787	876	904	977	2,505	3,544	5,485
Income Before Provision for Income Taxes	4,868	6,195	4,837	3,714	4,872	3,737	4,513	3,578	19,614	16,700	13,383
Provision for income taxes	1,588	1,991	1,551	1,026	1,516	1,125	1,198	1,034	6,156	4,873	3,918
Net Income Attributable to Northrim BanCorp	3,162	4,066	3,142	2,576	3,255	2,506	3,182	2,455	12,946	11,398	9,066
Northrim Bancorp, Inc. [Member]
Interest income									198	51	57
Other income									209	92	270
Total Income									14,392	12,602	10,406
Interest expense									493	466	470
Administrative and other expenses									1,646	1,737	1,579
Total Expense									2,139	2,203	2,049
Income Before Provision for Income Taxes									12,253	10,399	8,357
Provision for income taxes									(693)	(999)	(709)
Net Income Attributable to Northrim BanCorp									12,946	11,398	9,066
Northrim Bank [Member] | Northrim Bancorp, Inc. [Member]
Net income (loss) from subsidiary									13,950	12,442	10,246
Northrim Investment Services Company [Member] | Northrim Bancorp, Inc. [Member]
Net income (loss) from subsidiary									$ 35	$ 17	$ (167)