Document and Entity Information [Abstract] Document And Entity Information [Abstract] Statement [Table] Statement [Line Items] FinancingReceivableRecordedInvestmentPastDueLineItems Nonaccrual Loans By Major Loan Type [Line Items] Document Type Document Period End Date Amendment Flag Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date Entity Filer Category Document Fiscal Year Focus Document Fiscal Period Focus Entity Common Stock, Shares Outstanding Consolidated Balance Sheets [Abstract] ASSETS ASSETS Cash and Due from Banks Cash and due from banks Cash and Due from Banks, Total Overnight Investments Interest bearing deposits in other banks Investment securities available for sale Available-for-sale Securities, Fair Value Available-for-sale Securities, Total Investment securities held to maturity Held-to-maturity Securities, Total Marketable Securities Total portfolio investments Investment in Federal Home Loan Bank stock Investment in Federal Home Loan Bank stock, at cost Investment in Federal Home Loan Bank stock Loans held for sale Loans and Leases Receivable, Net of Deferred Income Loans Loans and Leases Receivable, Net of Deferred Income, Total Loans and Leases Receivable, Allowance Allowance for loan losses Loans and Leases Receivable, Allowance, Ending Balance Loans and Leases Receivable, Allowance, Beginning Balance Loans and Leases Receivable, Allowance, Total Allowance Net loans Net loans Accounts Receivable, Net Purchased receivables, net Accounts Receivable, Net, Total Decrease in accrued interest receivable Accrued interest receivable Real Estate Acquired Through Foreclosure Other real estate owned Premises and equipment, net Property, Plant and Equipment, Net, Ending Balance Property, Plant and Equipment, Net, Beginning Balance Property, Plant and Equipment, Net, Total Reflects the carrying amount of goodwill as of the balance sheet date, which is the cumulative amount paid and (if applicable) the fair value of any noncontrolling interest in the acquiree, adjusted for any amortization recognized prior to the adoption of any changes in generally accepted accounting principles (as applicable) and for any impairment charges, in excess of the fair value of net assets acquired in one or more business combination transactions. Additionally, reflects the carrying amounts of all other intangible assets as of the balance sheet date, net of accumulated amortization and impairment charges. Goodwill and Intangible Assets Goodwill and intangible assets Other Assets Other assets Other Assets, Total Assets element Total assets Assets LIABILITIES Abstract LIABILITIES Demand Demand Deposit Accounts, Total Interest-bearing Deposit Liabilities Interest-bearing demand Interest-bearing Deposit Liabilities, Total Savings Amount of interest bearing deposits with no stated maturity, which may include savings accounts and money-market deposit accounts (MMDAs). Transactions in these are be somewhat more limited than demand accounts and they share some of the characteristics of a money market account. Alaska CDs Money market Certificates of Deposit, less than $100,000 Certificates of deposit less than $100,000 Certificates of Deposit, more than $100,000 Certificates of deposit greater than $100,000 Time Deposits, $100,000 or More, Total Deposits Total deposits Total deposits Securities sold under repurchase agreements Other borrowings Borrowings Junior Subordinated Notes Junior subordinated debentures Junior Subordinated Notes, Total Other Liabilities Other liabilities Other Liabilities, Total Liabilities Total liabilities SHAREHOLDERS' EQUITY Shareholders' Equity Preferred Stock, $1 par value, 2,500,000 shares authorized, none issued or outstanding Preferred Stock, Value, Issued, Ending Balance Preferred Stock, Value, Issued, Beginning Balance Preferred stock, $1 par value, 2,500,000 shares authorized, none issued or outstanding Preferred Stock, Value, Issued, Total Common Stock, Value, Issued Common Stock, Value, Issued, Ending Balance Common Stock, Value, Issued, Beginning Balance Common stock, $1 par value, 10,000,000 shares authorized, 6,468,690, 6,466,763 and 6,429,476 shares issued and outstanding at March 31, 2012, December 31, 2011, and March 31, 2011, respectively Common Stock, Value, Issued, Total Common stock, $1 par value, 10,000,000 shares authorized, 6,446,763 and 6,427,237 shares issued and outstanding at December 31, 2011 and 2010, respectively Additional paid-in capital Additional Paid in Capital, Ending Balance Additional Paid in Capital, Beginning Balance Additional Paid in Capital, Total Retained earnings Retained Earnings (Accumulated Deficit), Ending Balance Retained Earnings (Accumulated Deficit), Beginning Balance Retained Earnings (Accumulated Deficit), Total Accumulated Other Comprehensive Income (Loss), Net of Tax Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance Accumulated other comprehensive income Accumulated Other Comprehensive Income (Loss), Net of Tax, Total Stockholders' Equity Attributable to Parent Ending balance, value Beginning balance, value Balance as of September 30, 2010 Total Northrim BanCorp shareholders' equity Noncontrolling interest Stockholders' Equity Attributable to Noncontrolling Interest, Ending Balance Stockholders' Equity Attributable to Noncontrolling Interest, Beginning Balance Stockholders' Equity Attributable to Noncontrolling Interest, Total Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Balance Balance Equity Total shareholders' equity Total liabilities and shareholders' equity Total liabilities and shareholders' equity Preferred Stock, Par Value Preferred stock, par value Preferred Stock, Shares Authorized Preferred stock, shares authorized Preferred Stock, Issued Preferred stock, issued Preferred Stock, Shares Issued, Total Preferred Stock, Outstanding Preferred Stock, Shares Outstanding, Ending Balance Preferred Stock, Shares Outstanding, Beginning Balance Preferred stock, outstanding Common Stock, Par Value Common stock, par value Common Stock, Shares Authorized Common stock, shares authorized Common Stock, Shares Issued Balance, shares Balance, shares Common stock, shares issued Common Stock, Shares, Issued, Total Common Stock, Shares Outstanding Common Stock, Shares, Outstanding, Ending Balance Common Stock, Shares, Outstanding, Beginning Balance Common stock, shares outstanding Consolidated Statements Of Income [Abstract] Legal Entity [Axis] Entity [Domain] Entity [Domain] RML [Member] Rml [Member] RML [Member] Interest Income Interest and fees on loans Interest and Fee Income, Loans and Leases, Total Securities available for sale Interest on investment securities-available for sale Securities held to maturity Interest on investment securities-held to maturity Interest on overnight investments Interest on deposits in other banks Interest Income, Deposits with Financial Institutions, Total Interest and Dividend Income, Operating Total Interest Income Interest Expense Interest expense on deposits, borrowings and junior subordianted debentures Interest Expense, Total Interest Income (Expense), Net Net Interest Income Provision for loan losses Provision for loan losses Provision for loan losses Net Interest Income After Provision for Loan Losses Net Interest Income After Provision for Loan Losses Other Operating Income Interest Income, Purchased Receivables Purchased receivable income Fees and Commissions, Depositor Accounts Service charges on deposit accounts Income from the sale and service of employee benefit plans through affiliate. Employee benefit plan income Reflects revenue received from electronic banking services such as point-of-sale and ATM transaction fees. Electronic banking income Equity in earning from investment in affiliate. Earnings from affiliates are recorded using the equity method of accounting. Equity in earnings (loss) from entity Equity in earnings (loss) from entity Equity in earnings (loss) from RML Rental Income, Nonoperating Rental income Gain on sale of securities Gain (Loss) on Sale of Securities, Net, Total Other income Noninterest Income Total Other Operating Income Other Operating Expenses Other Operating Expense Salaries and other personnel expense Labor and Related Expense, Total Occupancy, Net Occupancy Marketing expense Professional and outside services Equipment expense Software Expense Software expense Amortization of low income housing tax investments. Amortization Of Low Income Housing Tax Investments Amortization of low income housing tax investments Reflects expenses directly associated with providing internet banking products and services. Internet Banking Expense Internet banking expense Insurance expense Other real estate owned expense net, including impairment Other real estate owned expense net, including impairment OREO (income) expense, net rental income and gains on sale Intangible asset amortization expense Intangible asset amortization expense Other Noninterest Expense Other operating expense Total Other Operating Expense Noninterest Expense Total Other Operating Expense Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Cumulative Effects of Changes in Accounting Principles, Noncontrolling Interest Income Before Provision for Income Taxes Income Before Provision for Income Taxes Income Tax Expense (Benefit) Provision for income taxes Income Tax Expense (Benefit), Total Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Net income Net Income Net income Net income attributable to the noncontrolling interest Less: Net income attributable to the noncontrolling interest Net Income (Loss) Attributable to Noncontrolling Interest, Total Net income attributable to Northrim BanCorp Net Income Attributable to Northrim BanCorp Net Income Attributable to Northrim BanCorp Earnings Per Share, Basic Earnings Per Share, Basic, Total Earnings Per Share, Diluted Earnings Per Share, Diluted, Total Weighted Average Shares Outstanding, Basic Weighted Average Number of Shares Outstanding, Basic, Total Weighted Average Shares Outstanding, Diluted Weighted Average Number of Shares Outstanding, Diluted, Total Consolidated Statements Of Comprehensive Income [Abstract] Other comprehensive income, net of tax: Change in unrealized holding gain (loss) on available for sale investment securities, net of related income tax effect Change in unrealized holding loss on available for sale securities Available-for-sale Securities, Change in Net Unrealized Holding Gain (Loss), Net of Tax, Total Change in unrealized holding gain (loss) on available for sale securities, net of tax Other Comprehensive Income, Other, Net of Tax Other comprehensive income Other comprehensive income Comprehensive Income, Net of Tax, Including Portion Attributable to Noncontrolling Interest Total Comprehensive Income Comprehensive income Less: comprehensive income attributable to the noncontrolling interest Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Less: comprehensive income attributable to the noncontrolling interest Less: comprehensive income attributable to the noncontrolling interest Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest, Total Total Comprehensive Income Total Comprehensive Income Comprehensive income attributable to Northrim BanCorp Consolidated Statements Of Changes In Shareholders' Equity [Abstract] Statement, Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common Stock [Member] Common Stock [Member] Additional Paid In Capital [Member] Additional Paid-In Capital [Member] Retained Earnings [Member] Retained Earnings [Member] Accumulated Other Comprehensive Income [Member] Accumulated Other Comprehensive Income [Member] Noncontrolling Interest [Member] Noncontrolling Interest [Member] Dividends, Cash Cash dividend declared Cash dividend declared Dividends, Cash, Total Stock option expense Stock option expense Stock option expense Exercise of stock options, shares Exercise of stock options, shares Exercise of stock options, value Exercise of stock options Excess tax benefits from share-based payment arrangements element Excess tax benefits from share-based payment arrangements Distributions to noncontrolling interest Distributions to noncontrolling interest Consolidated Statement Of Cash Flows [Abstract] Operating Activities: Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities: Security (gains), net Security gains, net Gain (Loss) on Sale of Investments, Total The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Depreciation and amortization of premises and equipment The amount of expense recognized in the current period that reflects the allocation of the cost of software assets over the their useful lives. Amortization of software Intangible asset amortization Amortization of Intangible Assets, Total Other Depreciation and Amortization Amortization of investment security premium, net of discount accretion Deferred tax liability (benefit) Deferred tax(benefit) liability Stock-based compensation Stock-based compensation expense Share-based Compensation, Total Excess tax benefits from share-based payment arrangements Excess tax benefits from share-based payment arrangements Deferral of loan fees and costs, net Deferral of loan fees and costs, net Purchases of loans held for sale Purchases of loans held for sale Payments to Purchase Loans Held-for-sale, Total Proceeds from the sale of loans held for sale Proceeds from Sale of Loans Held-for-sale, Total The net gain (loss) resulting from sales and other disposals of other real estate owned. Gain (Loss) on the Sale of Other Real Estate Owned Gain on sale of other real estate owned Gain on sale of other real estate owned Earnings in excess of proceeds from entity. Earnings in excess of proceeds from entity Equity in undistributed earnings from mortgage affiliate Net changes in assets and liabilities: Increase Decrease In Accrued Interest Receivable Net (Increase) decrease in accrued interest receivable Decrease in accrued interest receivable Increase (Decrease) in Other Operating Assets Decrease in other assets (Increase) decrease in other assets Increase (Decrease) in Other Operating Assets, Total Increase (Decrease) in Other Operating Liabilities (Decrease) in other liabilities Increase (Decrease) in Other Operating Liabilities, Total Net Cash Provided by (Used in) Operating Activities Net Cash Provided by Operating Activities Investing Activities: Purchases of investment securities-available-for-sale Purchases of investment securities-available-for-sale Payments to Acquire Available-for-sale Securities, Total Proceeds from sales/maturities of securities-available-for-sale Proceeds from sales/maturities of securities-available-for-sale Proceeds from Sale and Maturity of Available-for-sale Securities, Total Proceeds from calls/maturities of securities-held-to-maturity Payments to Acquire Other Receivables Investment in purchased receivables Investment in (repayment from) purchased receivables Proceeds from Principal Repayments on Loans and Leases Held-for-investment Loan paydowns, net of new advances Loan advances, net of paydowns Gain on sale of other real estate owned Proceeds from sale of other real estate owned The cash outflow for capital expenditures associated with other real estate owned. Investment in other real estate owned The cash outflow associated with loans made to Elliott Cove, net of cash inflow of repayments on the loan. Loan to entity, net of repayments Loan to Elliott Cove, net of repayments Purchases of premises and equipment Purchases of premises and equipment Payments to Acquire Property, Plant, and Equipment, Total Net Cash Provided by (Used in) Investing Activities Net Cash (Used) Provided by Investing Activities Financing Activities: (Decrease) increase in deposits Increase in deposits Increase (Decrease) in Deposits, Total Increase in securities sold under repurchase agreements (Decrease) in securities sold under repurchase agreements Increase (Decrease) in Federal Funds Purchased and Securities Sold under Agreements to Repurchase, Net, Total (Decrease) increase in borrowings Paydowns on borrowings Proceeds from (Repayments of) Debt, Total Paydowns on borrowings Distributions to minority interest Distributions to noncontrolling interest Distributions to noncontrolling interest Excess tax benefit payment arrangements Excess tax benefits from share-based payment arrangements Payments of Dividends Cash dividends paid Cash dividends paid Payments of Dividends, Total Net Cash Provided by (Used in) Financing Activities Net Cash (Used) Provided by Financing Activities Net Increase in Cash and Cash Equivalents Net Increase in Cash and Cash Equivalents Cash and Cash Equivalents, Period Increase (Decrease), Total Cash and Cash Equivalents, at Carrying Value Cash and Cash Equivalents at End of Period Cash and Cash Equivalents at Beginning of Period Cash and Cash Equivalents, at Carrying Value, Total Supplemental Information: Income taxes paid Income Taxes Paid, Net, Total Interest paid Interest Paid, Net, Total Transfer of loans to other real estate owned Loans made to facilitate sales of other real estate owned Loans made to facilitate sales of other real estate owned Dividends Payable, Amount Cash dividends declared but not paid Basis Of Presentation [Abstract] Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Basis Of Presentation Significant Accounting Policies And Recent Accounting Pronouncements [Abstract] Significant Accounting Policies [Text Block] Significant Accounting Policies And Recent Accounting Pronouncements Cash And Cash Equivalents [Abstract] Cash and Cash Equivalents Disclosure [Text Block] Cash And Cash Equivalents Investment Securities [Abstract] Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Investment Securities Loans Held For Sale [Abstract] Loans held for sale. Loans Held for Sale [Text Block] Loans Held For Sale Loans Loans [Abstract] Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Loans Allowance For Loan Losses [Abstract] Allowance For Loan Losses Nonperforming Assets And Loans Measure For Impairment [Text Block] Allowance For Loan Losses Goodwill And Other Intangibles [Abstract] Goodwill and Other Intangibles element Goodwill And Other Intangibles Deposit Activities [Abstract]