Consolidated Statements Of Changes In Shareholders' Equity (USD $) In Thousands, except Share data	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income [Member]	Non-controlling Interest [Member]	Total
Beginning balance, value at Dec. 31, 2011	$ 6,467	$ 53,164	$ 65,469	$ 283	$ 52	$ 125,435
Beginning balance, shares at Dec. 31, 2011	6,467,000
Cash dividend declared			(3,673)			(3,673)
Stock based compensation expense		454				454
Exercise of stock options, shares	45,000
Exercise of stock options	45	(213)				(168)
Excess tax benefits from share-based payment		233				233
Distributions to noncontrolling interest					(471)	(471)
Other comprehensive income				1,085		1,085
Net income attributable to the noncontrolling interest					512	512
Net income attributable to Northrim BanCorp			12,946			12,946
Ending balance, value at Dec. 31, 2012	6,512	53,638	74,742	1,368	93	136,353
Ending balance, shares at Dec. 31, 2012	6,512,000					6,511,649
Cash dividend declared			(985)			(985)
Stock based compensation expense		112				112
Exercise of stock options, shares	1,000
Exercise of stock options	1	(7)				(6)
Excess tax benefits from share-based payment		10				10
Distributions to noncontrolling interest					(104)	(104)
Other comprehensive income				(40)		(40)
Net income attributable to the noncontrolling interest					90	90
Net income attributable to Northrim BanCorp			2,674			2,674
Ending balance, value at Mar. 31, 2013	$ 6,513	$ 53,753	$ 76,431	$ 1,328	$ 79	$ 138,104
Ending balance, shares at Mar. 31, 2013	6,513,000					6,513,096