Subordinated Debentures (Details) $ / shares in Units, $ in Thousands		12 Months Ended
	Nov. 30, 2025 USD ($)	Dec. 31, 2025 USD ($)	Dec. 31, 2024 USD ($) $ / shares	Dec. 31, 2023 USD ($)	Dec. 31, 2005 USD ($)
Subordinated Borrowing [Line Items]
Investment in unconsolidated trust		$ 84,172	$ 85,819
Tenor spread adjustment (as a percent)			0.0026
Interest expense		42,769	$ 40,736	$ 28,695
Amortization of debt issuance costs		14	$ 0	0
Subordinated Notes Due 2035 | Senior Subordinated Notes
Subordinated Borrowing [Line Items]
Basis plus LIBOR	3.48%
Face amount	$ 60,000
Stated percentage	6.875%
Redemption price, percentage	100.00%
Interest costs incurred		401
Debt issuance costs, gross		1,400
Amortization of debt issuance costs		$ 14
Redemption price, percentage of principal amount redeemed	100.00%
Northrim Statutory Trust 2
Subordinated Borrowing [Line Items]
Investment in unconsolidated trust					$ 10,000
Subordinated debentures					$ 10,300
SOFR period			90 days
Basis plus LIBOR			1.37%
Liquidation preference per capital security (in USD per share) | $ / shares			$ 1,000
Interest rate (as a percent)		5.35%	5.99%
Interest expense		$ 612	$ 717	$ 693