Summary Of Significant Accounting Policies (Calculation Of Earnings Per Share) (Details) (USD $) In Thousands, except Share data, 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
Net income	$ 3,162	$ 4,066	$ 3,142	$ 2,576	$ 3,255	$ 2,506	$ 3,182	$ 2,455	$ 12,946	$ 11,398	$ 9,066
Weighted Average Shares Outstanding, Basic									6,477,266	6,438,625	6,398,329
Dilutive effect of potential common shares from awards granted under equity incentive program									63,344	116,136	82,576
Total									6,574,993	6,554,761	6,480,905
Earnings per common share, Basic	$ 0.49	$ 0.63	$ 0.49	$ 0.40	$ 0.50	$ 0.39	$ 0.49	$ 0.38	$ 2.00	$ 1.77	$ 1.42
Earnings per common share, Dilutive	$ 0.48	$ 0.62	$ 0.48	$ 0.39	$ 0.50	$ 0.38	$ 0.49	$ 0.37	$ 1.97	$ 1.74	$ 1.40
Northrim Bancorp, Inc. [Member]
Net income									$ 12,946	$ 11,398	$ 9,066