Summary of Significant Accounting Policies (Policies)	6 Months Ended
Summary of Significant Accounting Policies (Policies)	Jun. 30, 2018
Summary of Significant Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accounting and reporting policies of Severn Bancorp, Inc. and subsidiaries (the “Company”) conform to accounting principles generally accepted in the United States of America (“U.S.”) (“GAAP”) and prevailing practices within the financial services industry for interim financial information and Rule 8‑01 of Regulation S-X. Accordingly, they do not include all of the information and notes required for complete financial statements and prevailing practices within the banking industry. In the opinion of management, all adjustments (comprising only of those of a normal recurring nature) necessary for a fair presentation of the results of operations for the interim periods presented have been made. The results of operations for the three and six months ended June 30, 2018 are not necessarily indicative of the results that may be expected for the fiscal year ending December 31, 2018 or any other interim or future period. Events occurring after the date of the financial statements up to the date the financial statements were available to be issued were considered in the preparation of the consolidated financial statements. These statements should be read in conjunction with the financial statements and accompanying notes included in the Company’s 2017 Annual Report on Form 10‑K as filed with the Securities and Exchange Commission (“SEC”).
Principles of Consolidation	Principles of Consolidation The unaudited consolidated financial statements include the accounts of Severn Bancorp, Inc., and its wholly-owned subsidiaries, Mid-Maryland Title Company, Inc., SBI Mortgage Company and SBI Mortgage Company’s subsidiary, Crownsville Development Corporation, and its subsidiary, Crownsville Holdings I, LLC, and Severn Savings Bank, FSB (the “Bank”), and the Bank’s subsidiaries, Louis Hyatt, Inc., Homeowners Title and Escrow Corporation, Severn Financial Services Corporation, SSB Realty Holdings, LLC, SSB Realty Holdings II, LLC, and HS West, LLC. All intercompany accounts and transactions have been eliminated in the accompanying consolidated financial statements.
Use of Estimates	Use of Estimates The preparation of financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements, and affect the reported amounts of revenues earned and expenses incurred during the reporting period. Actual results could differ from those estimates. Estimates that could change significantly relate to the provision for loan losses and the related allowance for loan losses (“Allowance”), determination of impaired loans and the related measurement of impairment, valuation of investment securities and the determination of other-than-temporary-impairment (“OTTI”), valuation of real estate acquired through foreclosure, valuation of stock-based compensation, the assessment that a liability should be recognized with respect to any matters under litigation, and the calculation of current and deferred income taxes and the realizability of net deferred tax assets.
Cash Flows	Cash Flows We consider all highly liquid securities with original maturities of three months or less to be cash equivalents. For reporting purposes, assets grouped in the Consolidated Statements of Financial Condition under the captions “Cash and due from banks” and “Federal funds sold and interest-bearing deposits in other banks” are considered cash or cash equivalents. For financial statement purposes, these assets are carried at cost. Federal funds sold and interest-bearing deposits in other banks generally have overnight maturities and are in excess of amounts that would be recoverable under Federal Deposit Insurance Corporation (“FDIC”) insurance.
Reclassifications	Reclassifications Certain reclassifications have been made to amounts previously reported to conform to current period presentation.
Revenue Recognition	Revenue Recognition Accounting Standards Codification (“ASC”) 606, Revenue from Contracts with Customers, establishes principles for reporting information about the nature, amount, timing and uncertainty of revenue and cash flows arising from the entity's contracts to provide goods or services to customers. The core principle requires an entity to recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration that it expects to be entitled to receive in exchange for those goods or services recognized as performance obligations are satisfied. The majority of our revenue-generating transactions are not subject to ASC 606, including revenue generated from financial instruments, such as our loans, letters of credit, derivatives and investment securities, as well as revenue related to our mortgage-banking and mortgage servicing activities. Our revenue-generating activities that are within the scope of ASC 606, which are presented in our income statements as components of noninterest income, are service charges on deposit accounts, real estate commissions, real estate management fees, and title company revenue. Service Charges on Deposit Accounts Service charges on deposit accounts represent general service fees for monthly account maintenance and activity - or transaction-based fees and consist of transaction-based revenue, time-based revenue (service period), item-based revenue or some other individual attribute-based revenue. Revenue is recognized when our performance obligation is completed which is generally monthly for account maintenance services or when a transaction has been completed (such as a wire transfer). Payment for such performance obligations are generally received at the time the performance obligations are satisfied. Real Estate Commissions Real Estate Commissions represent commissions received on properties sold. Revenue is recognized when our performance obligation is completed, which is generally the time the property is sold and payment has been received. Real Estate Management Fees Real Estate Management Fees represent monthly fees received on property maintenance and management. We perform daily services for these fees and bill for those services on a monthly basis. We have determined that each day of the performance of the services represents a distinct service. The overall service of property management each day is substantially the same and has the same pattern of transfer (daily) over the term of the contract. Further, each distinct day of service represents a performance obligation that would be satisfied over time (over the length of the contract, not at a point in time) and has the same measure of progress (elapsed time). Management has therefore determined that property management services are a single performance obligation composed of a series of distinct services. In performing the daily management activities, the customer is simultaneously receiving and consuming the benefits provided by our performance of the contract. Revenue is earned evenly and daily over the life of the contract. For purposes of expedience, we record the fees when monthly invoices are processed. Each month contains 1/12 of the contract revenue. Title Company Revenue Title Company Revenue consists of revenue earned on performing title work for real estate transactions. The revenue is earned when the title work is performed. Payment for such performance obligations generally occurs at the time of the settlement of a real estate transaction. As such settlement is generally within 90 days of the performance of the title work, we recognize the revenue at the time of the settlement.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Pronouncements Adopted In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2014‑09, Revenue from Contracts with Customers, as amended by ASU 2015‑14, Revenue from Contracts with Customers: Deferral of the Effective Date, ASU 2016‑08, Revenue from Contracts with Customers: Principal Versus Agent Considerations (Reporting Revenue Gross Versus Net), ASU 2016‑10, Revenue from Contracts with Customers, Identifying Performance Obligations and Licensing, ASU 2016‑12, Revenue from Contracts with Customers: Narrow-Scope Improvements and Practical Expedients, ASU 2016‑20, Technical Corrections and Improvements to Topic 606, Revenue form Contracts with Customers, that provides accounting guidance for all revenue arising from contracts with customers and affects all entities that enter into contracts to provide goods or services to customers. The guidance also provides for a model for the measurement and recognition of gains and losses on the sale of certain nonfinancial assets, such as property and equipment, including real estate. We adopted the pronouncement on January 1, 2018 and elected the modified retrospective transition method. There was no material impact to the financial statements.. Our accounting policies and revenue recognition principles did not change materially as the principles of ASC 606 are largely consistent with the previous revenue recognition practices. See additional information on revenue recognition above. In January 2016, FASB issued ASU No. 2016‑01, Financial Instruments – Overall: Recognition and Measurement of Financial Assets and Financial Liabilities, which requires entities to measure equity investments at fair value and recognize changes on fair value in net income. The guidance also provides a new measurement alternative for equity investments that do not have readily determinable fair values and don’t qualify for the net asset value practical expedient. The standard requires entities to record changes in instrument–specific credit risk for financial liabilities measured under the fair value option in other comprehensive income, except for certain financial liabilities of consolidated collateralized financing entities. Entities also have to reassess the realizability of a deferred tax asset related to an available-for-sale (“AFS”) debt security in combination with their other deferred tax assets. The adoption of this standard did not have a material impact on the Company’s financial position, results of operations, or cash flows. In August 2016, FASB issued ASU No. 2016‑15, Classification of Certain Cash Receipts and Cash Payments, which provides guidance regarding the presentation of certain cash receipts and cash payments in the statement of cash flows, addressing eight specific cash flow classification issues, in order to reduce existing diversity in practice. The adoption of ASC No. 2016‑15 did not have a material impact on our financial position, results of operations, or cash flows. Pronouncements Issued In February 2016, FASB issued ASU 2016‑02, Leases, which requires a lessee to recognize the assets and liabilities that arise from all leases with a term greater than 12 months. The core principle requires the lessee to recognize a liability to make lease payments and a “right-of-use” asset. The accounting applied by the lessor is relatively unchanged. The ASU also requires expanded qualitative and quantitative disclosures. For public business entities, the guidance is effective for interim and annual reporting periods beginning after December 15, 2018 and mandates a modified retrospective transition for all entities. Early application is permitted. We have determined that the provisions of ASU No. 2016‑02 may result in an increase in assets to recognize the present value of the lease obligations, with a corresponding increase in liabilities, however, we do not expect this to have a material impact on our financial position, results of operations, or cash flows. In June 2016, FASB issued ASU No. 2016‑13, Financial Instruments – Credit Losses, which sets forth a current expected credit loss (“CECL”) model which requires the Company to measure all expected credit losses for financial instruments held at the reporting date based on historical experience, current conditions, and reasonable supportable forecasts. This replaces the existing incurred loss model and is applicable to the measurement of credit losses on financial assets measured at amortized cost and applies to some off-balance sheet credit exposures. This ASU is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. While we are currently in the process of evaluating the impact of the amended guidance on our Consolidated Financial Statements, we currently expect the Allowance to increase upon adoption given that the Allowance will be required to cover the full remaining expected life of the portfolio upon adoption, rather than the incurred loss model under current GAAP. The extent of this increase is still being evaluated and will depend on economic conditions and the composition of our loan and lease portfolio at the time of adoption. In March 2017, FASB issued ASU No. 2017‑08, Receivables - Nonrefundable Fees and Other costs, which provides guidance that calls for the shortening of the amortization period for certain callable debt securities held at a premium. The standard is effective for interim and annual reporting periods beginning after December 15, 2018. Early adoption is permitted. We do not expect the adoption of ASC No. 2017‑08 to have a material impact on our financial position, results of operations, or cash flows. In February 2018, FASB issued ASU No. 2018-02, Reclassification of Certain Tax Effects From Accumulated Other Comprehensive Income, which allows a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act. The ASU is effective for all entities for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early adoption is permitted. The Company does not expect the adoption of ASU No. 2018-02 to have a material impact on its financial position, results of operations, or cash flows.