Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Interest Income
Interest and fees on loans and loans held for sale	$ 55,041	$ 54,777	$ 56,166
Interest on investment securities available for sale	4,575	3,895	3,393
Interest on investment securities held to maturity	59	41	68
Interest on deposits in other banks	433	205	153
Total Interest Income	60,108	58,918	59,780
Interest Expense
Interest expense on deposits	1,707	1,870	1,939
Interest expense on securities sold under agreements to repurchase	34	30	23
Interest expense on borrowings	173	127	446
Interest expense on junior subordinated debentures	516	534	463
Total Interest Expense	2,430	2,561	2,871
Net Interest Income	57,678	56,357	56,909
Provision for loan losses	3,200	2,298	1,754
Net Interest Income After Provision for Loan Losses	54,478	54,059	55,155
Other Operating Income
Mortgage banking income	23,287	29,507	29,613
Gain on sale of Northrim Benefits Group	4,445	0	0
Purchased receivable income	2,975	2,347	2,287
Bankcard fees	2,597	2,670	2,671
Employee benefit plan income	2,506	3,770	3,651
Service charges on deposit accounts	1,614	1,998	2,103
Gain (loss) on sale of securities	11	(11)	271
Other income	3,039	2,982	4,012
Total Other Operating Income	40,474	43,263	44,608
Other Operating Expense
Salaries and other personnel expense	44,721	46,752	43,931
Occupancy expense	6,752	6,462	6,332
Data processing expense	5,549	4,879	4,313
Marketing expense	2,566	2,449	2,728
Professional and outside services	2,365	2,797	2,980
Insurance expense	1,161	1,023	1,339
OREO expense, net of rental income and gains on sale	837	98	190
Compensation expense - RML acquisition payments	130	4,775	4,094
Intangible asset amortization expense	100	135	258
Reserve (benefit) for purchased receivables	29	(10)	(138)
Loss on sale of premises and equipment	3	352	37
Other operating expense	6,940	6,568	6,581
Total Other Operating Expense	71,153	76,280	72,645
Income Before Provision for Income Taxes	23,799	21,042	27,118
Provision for income taxes	10,321	6,052	8,784
Net Income	13,478	14,990	18,334
Less: Net income attributable to the noncontrolling interest	327	579	551
Net Income Attributable to Northrim BanCorp, Inc.	$ 13,151	$ 14,411	$ 17,783
Earnings per share, basic (in USD per share)	$ 1.91	$ 2.09	$ 2.59
Earnings per share, diluted (in USD per share)	$ 1.88	$ 2.06	$ 2.56
Weighted Average Shares Outstanding, Basic (in shares)	6,889,621	6,883,663	6,859,209
Weighted Average Shares Outstanding, Diluted (in shares)	6,977,910	6,974,864	6,948,474