Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 5,830	$ 3,741	$ 9,892	$ 7,663
Securities available for sale:
Unrealized (losses) gains arising during the period	(119)	90	(1,107)	687
Reclassification of net (gains) losses included in net income (net of tax (benefit) expense) of $0 and $0 for the second quarter of 2018 and 2017, respectively, and $0 and $6 for the six months ended June 30, 2018 and 2017, respectively	0	0	0	(8)
Derivatives and hedging activities:
Unrealized gains arising during the period	154	0	621	0
Income tax benefit (expense) related to unrealized gains and losses	143	(31)	246	(254)
Other comprehensive income (loss), net of tax	178	59	(240)	425
Comprehensive income	6,008	3,800	9,652	8,088
Less: comprehensive income attributable to the noncontrolling interest	0	152	0	249
Comprehensive income attributable to Northrim BanCorp, Inc.	$ 6,008	$ 3,648	$ 9,652	$ 7,839