Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Interest Income
Interest and fees on loans and loans held for sale	$ 62,150	$ 57,542	$ 55,041
Interest on investment securities available for sale	6,572	5,481	4,230
Dividends on marketable equity securities	439	348	345
Interest on investment securities held to maturity	0	0	59
Interest on deposits in other banks	922	806	433
Total Interest Income	70,083	64,177	60,108
Interest Expense
Interest expense on deposits	4,961	2,307	1,707
Interest expense on securities sold under agreements to repurchase	40	50	34
Interest expense on borrowings	251	223	173
Interest expense on junior subordinated debentures	389	389	516
Total Interest Expense	5,641	2,969	2,430
Net Interest Income	64,442	61,208	57,678
(Benefit) provision for loan losses	(1,175)	(500)	3,200
Net Interest Income After (Benefit) Provision for Loan Losses	65,617	61,708	54,478
Other Operating Income
Mortgage banking income	24,201	20,844	23,287
Purchased receivable income	3,271	3,255	2,975
Gain (loss) on marketable equity securities	911	(625)	0
Interest rate swap income	964	84	26
Commercial servicing revenue	624	1,422	372
Gain on sale of securities	23	0	11
Gain on sale of Northrim Benefits Group	0	0	4,445
Employee benefit plan income	0	0	2,506
Other income	2,819	2,868	2,641
Total Other Operating Income	37,346	32,167	40,474
Other Operating Expense
Salaries and other personnel expense	51,317	44,650	44,721
Data processing expense	7,128	6,035	5,549
Occupancy expense	6,607	6,136	6,752
Professional and outside services	2,531	2,453	2,365
Marketing expense	2,373	2,318	2,566
Insurance expense	557	862	1,161
Compensation expense - RML acquisition payments	468	0	130
Intangible asset amortization expense	60	70	100
Impairment of equity method investment	0	804	686
OREO (income) expense, net of rental income and gains on sale	(193)	258	837
Other operating expense	5,990	6,214	6,286
Total Other Operating Expense	76,838	69,800	71,153
Income Before Provision for Income Taxes	26,125	24,075	23,799
Provision for income taxes	5,434	4,071	10,321
Net Income	20,691	20,004	13,478
Less: Net income attributable to the noncontrolling interest	0	0	327
Net Income Attributable to Northrim BanCorp, Inc.	$ 20,691	$ 20,004	$ 13,151
Earnings per share, basic (in USD per share)	$ 3.08	$ 2.91	$ 1.91
Earnings per share, diluted (in USD per share)	$ 3.04	$ 2.86	$ 1.88
Weighted Average Shares Outstanding, Basic (in shares)	6,708,622	6,877,573	6,889,621
Weighted Average Shares Outstanding, Diluted (in shares)	6,808,209	6,981,557	6,977,910
Bankcard fees
Other Operating Income
Revenue from contract with customer	$ 2,976	$ 2,811	$ 2,597
Service charges on deposit accounts
Other Operating Income
Revenue from contract with customer	$ 1,557	$ 1,508	$ 1,614