Employee Benefit Plans (Details) - USD ($)	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Accrued liability for plan	$ 1,800,000	$ 1,800,000
Increase (decrease) in non-qualified deferred compensation plan	59,000	24,000	$ (10,000)
Accrued employee benefits	2,000,000.0	2,000,000.0
Supplemental Employee Retirement Plan
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Contributions to supplemental plan	0	397,000	350,000
Accrued liability for plan	2,600,000	2,500,000
RML
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Contributions to supplemental plan	374,000	380,000	333,000
Accrued liability for plan	$ 939,000	2,100,000
Vesting period	10 years
401(k) Plan
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Mandatory 401(k) match	$ 1.00
Maximum annual employer 401(k) contribution	6.00%
Defined contribution plan cost	$ 2,900,000	2,100,000	2,000,000.0
401(k) Plan | RML
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Mandatory 401(k) match	$ 1.00
Maximum annual employer 401(k) contribution	3.00%
Northrim Non-Qualified Deferred Compensation Plan | Supplemental Employee Retirement Plan
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Contributions to supplemental plan	$ 256,000
Profit Sharing Plan
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Defined contribution plan cost	$ 6,300,000	$ 5,200,000	$ 2,500,000
Safe Harbor Retirement Plan
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Employer matching contribution, percent of match	100.00%
Employer matching contribution, percent of employees' gross pay	3.00%
Employer matching contribution, additional percent of match	50.00%
Employer matching contribution, additional percent of employees' gross pay	5.00%