Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 13,478	$ 14,990	$ 18,334
Securities available for sale:
Unrealized holding gains (losses) arising during the period	175	42	(795)
Reclassification of net (gains) losses included in net income (net of tax benefit (expense) $5, ($5), and $111 in 2017, 2016 and 2015, respectively)	(6)	6	(160)
Derivatives and hedging activities:
Unrealized holding gains arising during the period	184	0	0
Income tax (expense) benefit related to unrealized gains and losses	(141)	(33)	296
Other comprehensive income (loss), net of tax	212	15	(659)
Comprehensive income	13,690	15,005	17,675
Less: comprehensive income attributable to the noncontrolling interest	327	579	551
Comprehensive income attributable to Northrim BanCorp, Inc.	$ 13,363	$ 14,426	$ 17,124