Junior Subordinated Debentures (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2005
Subordinated Borrowing [Line Items]
Investment in unconsolidated trust	$ 85,819	$ 71,789
Junior subordinated debentures	10,310	10,310
Interest expense	$ 40,736	$ 28,695	$ 5,213
Northrim Statutory Trust 2
Subordinated Borrowing [Line Items]
Investment in unconsolidated trust				$ 10,000
Junior subordinated debentures				$ 10,300
SOFR period	90 days
LIBOR period	90 days
Liquidation preference per capital security (in USD per share)	$ 1,000
Interest rate (as a percent)	5.99%	7.02%
Interest expense	$ 717	$ 693	$ 326
Northrim Statutory Trust 2 | Secured Overnight Financing Rate (SOFR)
Subordinated Borrowing [Line Items]
Basis plus LIBOR	1.37%
Northrim Statutory Trust 2 | London Interbank Offered Rate (LIBOR)
Subordinated Borrowing [Line Items]
Basis plus LIBOR	1.37%