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, 2010	$ 6,427	$ 52,658	$ 57,339	$ 648	$ 50	$ 117,122
Beginning balance, shares at Dec. 31, 2010	6,427,000
Cash dividend declared			(2,411)			(2,411)
Stock based compensation expense		381				381
Exercise of stock options, shares	13,000
Exercise of stock options	13	(32)				(19)
Excess tax benefits from share-based payment arrangements		84				84
Distributions to noncontrolling interest					(315)	(315)
Change in unrealized holding gain on available for sale securities, net of tax				32		32
Net income attributable to the noncontrolling interest					328	328
Net income attributable to Northrim BanCorp			8,143			8,143
Ending balance, value at Sep. 30, 2011	6,440	53,091	63,071	680	63	123,345
Ending balance, shares at Sep. 30, 2011	6,440,000					6,440,241
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					6,466,763
Cash dividend declared			(2,686)			(2,686)
Stock based compensation expense		339				339
Exercise of stock options, shares	7,000
Exercise of stock options	7	(22)				(15)
Excess tax benefits from share-based payment arrangements		55				55
Distributions to noncontrolling interest					(341)	(341)
Change in unrealized holding gain on available for sale securities, net of tax				1,146		1,146
Net income attributable to the noncontrolling interest					394	394
Net income attributable to Northrim BanCorp			9,784			9,784
Ending balance, value at Sep. 30, 2012	$ 6,474	$ 53,536	$ 72,567	$ 1,429	$ 105	$ 134,111
Ending balance, shares at Sep. 30, 2012	6,474,000					6,473,680