Goodwill and Intangible Assets - Narrative (Details) - USD ($)	1 Months Ended	12 Months Ended
	Oct. 31, 2007	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 01, 2014	Apr. 01, 2014	Dec. 31, 2005
Finite-Lived Intangible Assets [Line Items]
Accumulated amortization for intangible assets		$ 6,700,000	$ 6,500,000
Goodwill recorded		22,334,000	22,334,000
Trade name intangible		950,000	950,000
Goodwill impairment		0	0
Intangible asset amortization expense		$ 258,000	289,000	$ 228,000
Northrim Benefits Group
Finite-Lived Intangible Assets [Line Items]
Equity interest percentage							40.10%
Alaska First
Finite-Lived Intangible Assets [Line Items]
Goodwill recorded	$ 1,800,000
CDI recorded	$ 1,300,000
Alaska Pacific Bank
Finite-Lived Intangible Assets [Line Items]
CDI recorded						$ 623,000
RML
Finite-Lived Intangible Assets [Line Items]
Goodwill recorded					$ 14,800,000
Trade name intangible					$ 950,000
Customer Relationships | Northrim Benefits Group
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets							$ 1,100,000
Estimated useful life, years		10 years
Accumulated amortization for intangible assets		$ 1,100,000	1,100,000	943,000
Core Deposits | Alaska First
Finite-Lived Intangible Assets [Line Items]
Estimated useful life, years	10 years
Accumulated amortization for intangible assets		1,300,000	1,100,000	$ 983,000
Core Deposits | Alaska Pacific Bank
Finite-Lived Intangible Assets [Line Items]
Estimated useful life, years	10 years
Accumulated amortization for intangible assets		$ 190,000	$ 85,000