Goodwill and Intangible Assets Disclosure [Abstract] Schedule of Intangible Assets and Goodwill Schedule of Intangible Assets and Goodwill [Table Text Block] Receivables [Abstract] Schedule of Accounts, Notes, Loans and Financing Receivable Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Schedule of Components of Leveraged Lease Investments Schedule of Components of Leveraged Lease Investments [Table Text Block] Schedule of Financing Receivables, Non Accrual Status Schedule of Financing Receivables, Non Accrual Status [Table Text Block] Schedule of Information Related to Purchased Credit Impaired Loans Schedule of Information Related to Purchased Credit Impaired Loans [Table Text Block] Tabular disclosure of purchased credit impaired loans. Schedule of Changes in Accretable Discount Related to Purchased Credit Impaired Loans Schedule of Changes in Accretable Discount Related to Purchased Credit Impaired Loans [Table Text Block] Tabular disclosure of change in accretable discount on purchased credit-impaired loans. Past Due Financing Receivables Past Due Financing Receivables [Table Text Block] Allowance for Credit Losses on Financing Receivables Allowance for Credit Losses on Financing Receivables [Table Text Block] Financing Receivable by Financial Instrument Performance Status Financing Receivable by Financial Instrument Performance Status [Table Text Block] Tabular disclosure of financing receivable by category of performance or non-performance status of financial instruments. Financing Receivable Credit Quality Indicators Financing Receivable Credit Quality Indicators [Table Text Block] Schedule of Allowance for Loan Losses by Portfolio Segment Schedule of Allowance for Loan Losses by Portfolio Segment [Table Text Block] Tabular disclosure of allocation of allowance for loan and lease losses by portfolio segment based on methodology used to evaluate loans and leases for impairment. Troubled Debt Restructurings on Financing Receivables Troubled Debt Restructurings on Financing Receivables [Table Text Block] Impaired Financing Receivables Impaired Financing Receivables [Table Text Block] Summary of Loans Acquired Loans Acquired Record [Table Text Block] Tabular disclosure of loans acquired in mergers and acquisitions are recorded at fair value. Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative liability held as collateral Derivative Liability, Collateral, Right to Reclaim Cash, Offset Fair value of net derivatives Derivative, Fair Value, Net Statement of Comprehensive Income [Abstract] Unrealized (losses) gains, tax (benefit) expense Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, Tax Reclassification adjustment for net gain on sale realized in net income, tax (expense) benefit Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax Reclassification adjustment for net (gain) realized on transfer of investment securities available for sale to trading, tax (expense) benefit Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Investment Transferred From Available for sale To Trading Tax Amount of tax expense (benefit) for reclassification adjustment from accumulated other comprehensive income (loss) for unrealized gain (loss) of investment classified as available-for-sale transferred to trading. Unrealized investment (losses) gains, tax (benefit) expense Other Comprehensive Income (Loss), Securities, Available-for-sale, Tax Change in unfunded pension liability related to unrealized loss, prior service cost and transition obligation, tax expense (benefit) Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Tax Investments, Debt and Equity Securities [Abstract] Debt Securities, Held-to-maturity [Table] Debt Securities, Held-to-maturity [Table] Financial Instrument [Axis] Financial Instrument [Axis] Financial Instruments [Domain] Financial Instruments [Domain] Mortgage-backed securities Collateralized Mortgage Backed Securities [Member] Schedule of Held-to-maturity Securities [Line Items] Schedule of Held-to-maturity Securities [Line Items] Held to maturity securities, amortized cost Debt Securities, Held-to-maturity, Maturity, without Single Maturity Date, Amortized Cost Held to maturity securities, gross unrealized gains Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain Held to maturity securities, gross unrealized losses Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss Held to maturity securities, fair value Debt Securities, Held-to-maturity, Maturity, without Single Maturity Date, Fair Value Segment Reporting [Abstract] Schedule of Segment Reporting Information, by Segment Schedule of Segment Reporting Information, by Segment [Table Text Block] Earnings Per Share [Abstract] Schedule of Earnings Per Share, Basic and Diluted Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Business Combinations [Abstract] Business Combinations Business Combination Disclosure [Text Block] Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] The 2007 Long-Term Incentive Plan The 2007 Long-Term Incentive Plan [Member] The stock-based compensation plan approved in 2007, called the 2007 Long-Term Incentive Plan. The 2010 Long-Term Incentive Plan The 2010 Long-Term Incentive Plan [Member] The stock-based compensation plan approved in 2010, called the 2010 Long-Term Incentive Plan. Award Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Restricted Stock Units (RSUs) Restricted Stock Units (RSUs) [Member] Performance Shares Performance Shares [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Number of shares available for grant Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Performance shares, minimum target (as a percent) Share based Compensation Arrangements By Share based Payment Award, Performance Shares, Minimum Target Represents the minimum percentage of PSA's or PSU's earned. Performance shares, maximum target (as a percent) Share based Compensation Arrangements By Share based Payment Award, Performance Shares, Maximum Target Represents the maximum percentage of PSA's or PSU's earned. Number of unvested options (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares Share based compensation expense Allocated Share-based Compensation Expense Unrecognized compensation costs Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized Unrecognized compensation costs, period of recognition Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Income Statement [Abstract] Interest income: Interest Income (Expense), Net [Abstract] Interest and fees on loans and leases Interest and Fee Income, Loans and Leases Interest on cash and cash equivalents Interest Income, Deposits with Financial Institutions Interest on investment securities: Interest and Dividend Income, Securities, by Taxable Status [Abstract] Taxable Interest Income, Securities, Operating, Taxable Non-taxable Interest Income, Securities, Operating, Tax Exempt Dividends Dividend Income, Operating Total interest income Interest and Dividend Income, Operating Interest expense: Interest Expense [Abstract] Interest on deposits Interest Expense, Deposits Interest on short-term borrowings Interest Expense, Short-term Borrowings Interest on FHLB advances and other borrowings Interest Expense, Long-term Debt Interest on subordinated notes Interest Expense, Subordinated Notes and Debentures Interest on junior subordinated debentures Interest Expense, Junior Subordinated Debentures Total interest expense Interest Expense Net interest income Interest Income (Expense), Net Provision for loan and lease losses Provision for Loan and Lease Losses Net interest income after provision for loan and lease losses Interest Income (Expense), after Provision for Loan Loss Noninterest income: Noninterest Income [Abstract] Fees for wealth management services Fees For Wealth Management Services Fees For Wealth Management Services Insurance commissions Insurance Commissions and Fees Capital markets revenue Principal Transactions Revenue, Net Service charges on deposits Service Charges On Deposits Service Charges On Deposits Loan servicing and other fees Fees and Commissions, Mortgage Banking and Servicing Net gain on sale of loans Gain (Loss) on Sale of Mortgage Loans Net gain on sale of investment securities available for sale Debt and Equity Securities, Realized Gain (Loss) Net gain (loss) on sale of other real estate owned (OREO) Gains (Losses) on Sales of Other Real Estate Dividends on FHLB and FRB stock Other Interest and Dividend Income Other operating income Noninterest Income, Other Operating Income Total noninterest income Noninterest Income Noninterest expenses: Noninterest Expense [Abstract] Salaries and wages Salary and Wage, NonOfficer, Excluding Cost of Good and Service Sold Employee benefits Other Labor-related Expenses Occupancy and bank premises Occupancy, Net Furniture, fixtures, and equipment Equipment Expense Advertising Advertising Expense Amortization of intangible assets Amortization of Intangible Assets Due diligence, merger-related and merger integration expenses Business Combination, Acquisition Related Costs Professional fees Professional Fees Pennsylvania bank shares tax Taxes, Miscellaneous Information technology Information Technology and Data Processing Other operating expenses Other Noninterest Expense Total noninterest expenses Noninterest Expense Income before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Income tax expense Income Tax Expense (Benefit) Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Net (loss) income attributable to noncontrolling interest Net Income (Loss) Attributable to Noncontrolling Interest Net income attributable to Bryn Mawr Bank Corporation Net Income (Loss) Attributable to Parent Basic earnings per common share (in dollars per share) Earnings Per Share, Basic Diluted earnings per common share (in dollars per share) Earnings Per Share, Diluted Dividends paid or accrued per share (in dollars per share) Common Stock, Dividends, Per Share, Cash Paid Or Accrued Common Stock, Dividends, Per Share, Cash Paid Or Accrued Weighted-average basic shares outstanding Weighted Average Number of Shares Outstanding, Basic Dilutive shares Weighted Average Number Diluted Shares Outstanding Adjustment Denominator for diluted earnings per share – adjusted weighted average shares outstanding Weighted Average Number of Shares Outstanding, Diluted Fair Value Disclosures [Abstract] Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum Minimum [Member] Maximum Maximum [Member] SEC Schedule, 12-09, Valuation Allowances and Reserves Type [Axis] SEC Schedule, 12-09, Valuation Allowances and Reserves Type [Axis] SEC Schedule, 12-09, Valuation Allowances and Reserves [Domain] SEC Schedule, 12-09, Valuation Allowances and Reserves [Domain] Allowance for Loan and Lease Loss SEC Schedule, 12-09, Allowance, Loan and Lease Loss [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Discount on appraisals of secured collateral (as a percent) Fair Value Assumptions Discount On Appraisals Of Collateral Securing Loan The subjective discount on appraisals of the collateral securing a loan used in valuing an instrument. Valuation allowance, period increase (decrease) SEC Schedule, 12-09, Valuation Allowances and Reserves, Period Increase (Decrease) Subordinated Debt [Abstract] Schedule of Long-term Debt Instruments Schedule of Long-term Debt Instruments [Table Text Block] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Subordinated Debt Subordinated Debt [Member] Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] LIBOR London Interbank Offered Rate (LIBOR) [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Subordinated notes – due 2027 2027 Notes [Member] Represents the fixed-to-floating rate subordinated notes due 2027. Subordinated notes – due 2025 2025 Notes [Member] Represents the fixed-to-floating rate subordinated notes due 2025. Debt Instrument [Line Items] Debt Instrument [Line Items] Subordinated debt Subordinated Debt Stated interest rate Debt Instrument, Interest Rate, Stated Percentage Basis spread on variable rate Debt Instrument, Basis Spread on Variable Rate Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Domenick Domenick [Member] Domenick [Member] RBPI RBPI [Member] Information pertaining to Royal Bancshares of Pennsylvania, Inc. (RBPI). Hirshorn Hirshorn [Member] The entity Harry R. Hirshorn & Company, Inc. (“Hirshorn”) Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Common Class A Common Class A [Member] Common Class B Common Class B [Member] Business Acquisition [Line Items] Business Acquisition [Line Items] Consideration paid Business Combination, Consideration Transferred Cash paid at closing Payments to Acquire Businesses, Gross Number of contingent cash payments Business Combination, Contingent Consideration, Liability, Number of Payments Business Combination, Contingent Consideration, Liability, Number of Payments Maximum contingent payment per period Business Combination, Contingent Consideration, Liability, Maximum Payment Per Period Business Combination, Contingent Consideration, Liability, Maximum Payment Per Period Shares issued (in shares) Business Acquisition, Equity Interest Issued or Issuable, Number of Shares Conversion ratio of shares in acquirer bmtc_BusinessCombinationStockConsiderationConversionRatioOfSharesInAcquirer Represents the conversion ratio of shares in a business combination. Cash in lieu of fractional shares Cash in lieu of fractional shares Business combination consideration transferred equity interest cash paid in lieu of fractional shares. Cash-out of certain options Cash-out of certain options Represents the amount of equity interest cash out of certain options in a business combination. Warrants converted by acquirer bmtc_BusinessCombinationWarrantsConvertedByAcquirer Number of warrants converted by the acquirer in a business combination. Fair value of warrants assumed Fair value of warrants assumed Amount of warrants converted by the acquirer in a business combination. Number of securities called by warrants Class of Warrant or Right, Number of Securities Called by Warrants or Rights Goodwill, expected tax deductible amount Business Acquisition, Goodwill, Expected Tax Deductible Amount Loans held for investment, increase in nonaccretable difference bmtc_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesNonaccretableYieldPeriodIncreaseDecrease Amount of increase (decrease) to the nonaccretable difference acquired loans accounted for as debt securities, with evidence of deterioration of credit quality. Certain loans acquired in transfer accounted for as debt securities, accretable yield, period increase (decrease) Certain Loans Acquired in Transfer Accounted for as Debt Securities, Accretable Yield, Period Increase (Decrease) Number of contingent cash payments made Business Combination, Contingent Consideration, Liability, Number of Payments Made Business Combination, Contingent Consideration, Liability, Number of Payments Made Contingent consideration, maximum amount of installment payment per period bmtc_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHighEachInstallment Represents the maximum payment of each contingent consideration installment in a business combination. Debt issued Debt Instrument, Face Amount Fair Value, Assets Measured on Recurring and Nonrecurring Basis Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Table Text Block] Fair Value Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Fair Value [Abstract] Held to maturity securities, less than 12 months, fair value Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value Held to maturity securities, 12 months or longer, fair value Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value Held to maturity securities, fair value Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value Unrealized Losses Debt Securities, Held-to-maturity, Unrealized Loss Position, Accumulated Loss [Abstract] Held to maturity securities, less than 12 months, unrealized losses Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Held to maturity securities, 12 months or longer, unrealized losses Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Held to maturity securities, unrealized losses Debt Securities, Held-to-maturity, Unrealized Loss Position, Accumulated Loss Deposits [Abstract] Deposits Deposit Liabilities Disclosures [Text Block] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Customer Relationships Customer Relationships [Member] Core Deposits Core Deposits [Member] Off-Market Favorable Lease Off-Market Favorable Lease [Member] Trade Names Trade Names [Member] Noncompete Agreements Noncompete Agreements [Member] Consideration paid: Business Combination, Consideration Transferred [Abstract] Contingent payment liability (present value) Business Combination, Consideration Transferred, Liabilities Incurred Common shares issued (3,101,316) Business Combination, Consideration Transferred, Equity Interests Issued and Issuable Value of consideration Assets acquired: Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract] Cash and due from banks Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents Intangible assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill Premises and equipment Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment Other assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets Investment securities available for sale Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Marketable Securities Loans Loans The amount of loans receivable recognized as of the acquisition date. Deferred income taxes Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Assets Noncurrent Bank-owned life insurance Bank-owned life insurance Amount of bank owned life insurance assumed at the acquisition date. Accounts receivable Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables Total assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets Liabilities assumed: Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract] Accounts payable Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Accounts Payable Other liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other Deposits bmtc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDepositLiabilities Amount of deposit liabilities assumed at the acquisition date. FHLB and other long-term borrowings Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Long-term Debt Short-term borrowings bmtc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedShortTermDebt Amount of short term debt assumed at the acquisition date. Junior subordinated debentures bmtc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedJuniorSubordinatedDebentures The amount of junior subordinated debentures assumed which have been recognized as of the acquisition date. Unfavorable lease liability Unfavorable lease liability Amount of unfavorable lease liability assumed at the acquisition date. Total liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities Net assets acquired Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net Goodwill Goodwill Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward] Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward] Balance Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Accretion Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Accretion Reclassifications from nonaccretable difference Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Reclassifications from Nonaccretable Difference Additions/adjustments Additions/adjustments Amount of increase of reclassification from nonaccretable difference to the excess of a loan's cash flows expected to be collected over the investor's initial investment in acquired loans not accounted for as debt securities with evidence of deterioration of credit quality. Balance Statement of Financial Position [Abstract] Assets Assets [Abstract] Cash and due from banks Cash and Due from Banks Interest bearing deposits with banks Interest-bearing Deposits in Banks and Other Financial Institutions Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Investment securities available for sale, at fair value (amortized cost of $543,240 and $692,824 as of September 30, 2018 and December 31, 2017, respectively) Debt Securities, Available-for-sale Investment securities held to maturity, at amortized cost (fair value of $8,544 and $7,851 as of September 30, 2018 and December 31, 2017, respectively) Debt Securities, Held-to-maturity Investment securities, trading Debt Securities, Trading, and Equity Securities, FV-NI Loans held for sale Loans Receivable Held-for-sale, Net, Not Part of Disposal Group Portfolio loans and leases, originated Portfolio loans and leases, originated Amount originated before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements. Portfolio loans and leases, acquired Portfolio loans and leases, acquired Acquired amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Total portfolio loans and leases Loans and Leases Receivable, Gross Less: Allowance for originated loan and lease losses bmtc_LoansAndLeasesReceivableAllowanceOriginated Amount of allowance to cover probable credit losses on originated loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements. Less: Allowance for acquired loan and lease losses bmtc_LoansAndLeasesReceivableAllowanceAcquired Amount of allowance to cover probable credit losses on acquired loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements. Total allowance for loans and lease losses Loans and Leases Receivable, Allowance Net portfolio loans and leases Loans and Leases Receivable, Net Amount Premises and equipment, net Property, Plant and Equipment, Net Accrued interest receivable Interest Receivable Mortgage servicing rights Servicing Asset at Amortized Cost Bank owned life insurance Bank Owned Life Insurance Federal Home Loan Bank stock Federal Home Loan Bank Stock Intangible assets Intangible Assets, Net (Excluding Goodwill) Other investments Other Investments Other assets Other Assets Total assets Assets Liabilities Liabilities [Abstract] Deposits: Noninterest-bearing Noninterest-bearing Deposit Liabilities, Domestic Interest-bearing Interest-bearing Deposit Liabilities Total deposits Deposits Short-term borrowings Short-term Debt Long-term FHLB advances Long-term Federal Home Loan Bank Advances Subordinated notes Junior subordinated debentures Junior Subordinated Notes Accrued interest payable Interest Payable Other liabilities Other Liabilities Total liabilities Liabilities Shareholders' equity Stockholders' Equity Attributable to Parent [Abstract] Common stock, par value $1; authorized 100,000,000 shares; issued 24,532,745 and 24,360,049 shares as of September 30, 2018 and December 31, 2017, respectively and outstanding of 20,292,420 and 20,161,395 as of September 30, 2018 and December 31, 2017, respectively Common Stock, Value, Issued Paid-in capital in excess of par value Additional Paid in Capital, Common Stock Less: Common stock in treasury at cost - 4,240,325 and 4,198,654 shares as of September 30, 2018 and December 31, 2017, respectively Treasury Stock, Value Accumulated other comprehensive loss, net of tax Accumulated Other Comprehensive Income (Loss), Net of Tax Retained earnings Retained Earnings (Accumulated Deficit) Total Bryn Mawr Bank Corporation shareholders' equity Stockholders' Equity Attributable to Parent Noncontrolling interest Stockholders' Equity Attributable to Noncontrolling Interest Total shareholders' equity Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Total liabilities and shareholders' equity Liabilities and Equity Loans and Leases Receivable Disclosure [Table] Loans and Leases Receivable Disclosure [Table] Credit Loss Status [Axis] Credit Loss Status [Axis] Credit Loss Status [Domain] Credit Loss Status [Domain] Originated Financial Asset Originated [Member] Acquired Financial Asset Acquired and No Credit Deterioration [Member] Loans and Leases Receivable Disclosure [Line Items] Loans and Leases Receivable Disclosure [Line Items] Minimum lease payments receivable Capital Leases, Future Minimum Payments Receivable Unearned lease income Capital Leases, Net Investment in Direct Financing Leases, Deferred Income Initial direct costs and deferred fees Capital Leases, Net Investment in Direct Financing Leases, Initial Direct Costs Total Leases Capital Leases, Net Investment in Direct Financing Leases Investment Securities Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Financing Receivable Portfolio Segment [Axis] Financing Receivable Portfolio Segment [Axis] Financing Receivable Portfolio Segment [Domain] Financing Receivable Portfolio Segment [Domain] Commercial mortgage Commercial Mortgage Portfolio Segment [Member] Loan based on the mortgage of the borrower's commercial property in which the borrower receives the loan amount upfront. Home equity loans and lines Home Equity Loans And Lines Of Credit Portfolio Segment [Member] Home Equity Loans And Lines Of Credit [Member] Residential mortgage Residential Mortgage Loan Portfolio Segment [Member] Loan based on the mortgage of the borrower's residential property in which the borrower receives the loan amount upfront. Construction Construction Loans Portfolio Segment [Member] Construction Loans Portfolio Segment [Member] Commercial and industrial Commercial Portfolio Segment [Member] Consumer Consumer Portfolio Segment [Member] Leases Finance Leases Portfolio Segment [Member] Unallocated Unallocated Financing Receivables [Member] Purchased credit-impaired Financial Asset Acquired with Credit Deterioration [Member] Financial Asset Acquired With and Without Credit Deterioration Financial Asset Acquired With and Without Credit Deterioration [Member] Financial asset acquired with and without deteriorated credit quality. Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts, Notes, Loans and Financing Receivable [Line Items] Allowance on loans and leases: Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract] Individually evaluated for impairment Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment Collectively evaluated for impairment Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment Allowance on loans and leases Financing Receivable, Allowance for Credit Losses Carrying value of loans and leases: Loans and Leases Receivable, Gross, Carrying Amount [Abstract] Individually evaluated for impairment Financing Receivable, Individually Evaluated for Impairment Collectively evaluated for impairment Financing Receivable, Collectively Evaluated for Impairment Portfolio loans and leases Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract] Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Net Change in Unrealized Gains on Available-for- Sale Investment Securities Accumulated Net Investment Gain (Loss) Attributable to Parent [Member] Net Change in Unfunded Pension Liability Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] AOCI Attributable to Parent AOCI Attributable to Parent [Member] Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] AOCI Attributable to Parent, Net of Tax [Roll Forward] AOCI Attributable to Parent, Net of Tax [Roll Forward] Beginning balance Other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Ending balance Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Level 1 Fair Value, Inputs, Level 1 [Member] Level 2 Fair Value, Inputs, Level 2 [Member] Level 3 Fair Value, Inputs, Level 3 [Member] Measurement Basis [Axis] Measurement Basis [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Carrying Amount Reported Value Measurement [Member] Fair Value Estimate of Fair Value Measurement [Member] Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Contract [Domain] Derivative Contract [Domain] Interest rate swaps Interest Rate Swap [Member] RPAs purchased Risk Participation Agreements Purchased [Member] Represents information pertaining to risk participation agreements purchased. RPAs sold Risk Participation Agreements Sold [Member] Represents information pertaining to risk participation agreements sold. Financial assets: Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract] Cash and cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Investment securities - available for sale Investment securities – held to maturity Debt Securities, Held-to-maturity, Fair Value Loans held for sale Loans Held-for-sale, Fair Value Disclosure Net portfolio loans and leases Loans Receivable, Fair Value Disclosure MSRs bmtc_MortgageServicingRightsFairValueDisclosure Fair value portion of mortgage servicing rights. Derivative assets Derivative Asset Other assets Other Assets, Fair Value Disclosure Total financial assets Assets, Fair Value Disclosure Financial liabilities: Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract] Deposits Deposits, Fair Value Disclosure Short-term borrowings Short-term Debt, Fair Value Long-term FHLB advances Long-term FHLB advances Fair value portion of long-term FHLB advances and other borrowings. Subordinated notes bmtc_SubordinatedDebtFairValueDisclosure Fair value portion of subordinated debt. Junior subordinated debentures bmtc_JuniorSubordinatedDebtFairValueDisclosure Fair value portion of junior subordinated debt. Derivative liabilities Derivative Liability Other liabilities Other Liabilities, Fair Value Disclosure Total financial liabilities Financial and Nonfinancial Liabilities, Fair Value Disclosure Commitments and Contingencies Disclosure [Abstract] Financial Instruments With Off-Balance Sheet Risk, Contingencies and Concentration of Credit Risk Financial Instruments with off Balance Sheet Risk Contingencies and Concentration of Credit Risk [Text Block] The complete disclosure for financial instruments with off-balance sheet risk, contingencies and concentration of credit risk. Stock-Based Compensation Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Goodwill [Roll Forward] Goodwill [Roll Forward] Balance December 31, 2017 Common shares issued (2,562) Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Consideration Transferred Common shares issued (in shares) Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Consideration Transferred, Shares Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Consideration Transferred, Shares Loans bmtc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentLoans This element represents the amount of any measurement period adjustment (as defined) realized during the reporting period to loans acquired in connection with a business combination for which the initial accounting was incomplete. Other assets bmtc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentOtherAssets This element represents the amount of any measurement period adjustment (as defined) realized during the reporting period to other assets acquired in connection with a business combination for which the initial accounting was incomplete. Deferred income taxes bmtc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentDeferredIncomeTaxes This element represents the amount of any measurement period adjustment (As defined) Realized during the reporting period to deferred income taxes assumed in connection with a business combination for which the initial accounting was incomplete. Total Fair Value Adjustments bmtc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentTotal This element represents the amount of total measurement period adjustments (as defined) realized during the reporting period for items acquired in connection with a business combination for which the initial accounting was incomplete. Balance September 30, 2018 Investment securities available for sale, at fair value, amortized cost Debt Securities, Available-for-sale, Amortized Cost Investment securities held to maturity at amortized cost, fair value Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Common stock, authorized (in shares) Common Stock, Shares Authorized Common stock, issued (in shares) Common Stock, Shares, Issued Common stock, outstanding (in shares) Common Stock, Shares, Outstanding Treasury stock (in shares) Treasury Stock, Shares Accounting Policies [Abstract] Adopted Pronouncements and Pronouncements Not Yet Effective New Accounting Pronouncements, Policy [Policy Text Block] Organization, Consolidation and Presentation of Financial Statements [Abstract] Number of trusts acquired Number Of Trusts Acquired Number Of Trusts Acquired Share-based Compensation, Stock Options, Activity Share-based Compensation, Stock Options, Activity [Table Text Block] Schedule of Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Grant Date Intrinsic Value Schedule of Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Grant Date Intrinsic Value [Table Text Block] Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding and Exercisable Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding and Exercisable [Table Text Block] Schedule of Nonvested Restricted Stock Units Activity Schedule of Nonvested Restricted Stock Units Activity [Table Text Block] Schedule of Nonvested Performance-based Units Activity Schedule of Nonvested Performance-based Units Activity [Table Text Block] Subordinated Notes Subordinated Borrowings Disclosure [Text Block] Document And Entity Information [Abstract] Document And Entity Information [Axis] Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Trading Symbol Trading Symbol Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Document Type Document Type Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Amendment Flag Amendment Flag Entity Small Business Entity Small Business Entity Emerging Growth Company Entity Emerging Growth Company Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Schedule of Financing Receivable, Allowance for Credit Losses [Table] Schedule of Financing Receivable, Allowance for Credit Losses [Table] Financing Receivable, Allowance for Credit Losses [Line Items] Financing Receivable, Allowance for Credit Losses [Line Items] Financing Receivable, Allowance for Credit Losses [Roll Forward] Financing Receivable, Allowance for Credit Losses [Roll Forward] Balance Charge-offs Financing Receivable, Allowance for Credit Losses, Write-downs Recoveries Financing Receivable, Allowance for Credit Losses, Recovery Provision for loan and lease losses Balance Schedule of Financing Receivables Past Due [Table] Schedule of Financing Receivables Past Due [Table] Receivable Type [Axis] Receivable Type [Axis] Receivable [Domain] Receivable [Domain] Originated Loans Originated Loans [Member] Contractual rights to receive money on demand or on fixed or determinable dates that is recognized as an asset in the creditor's statement of originated loans position. Acquired Loans Acquired Loans [Member] Contractual rights to receive money on demand or on fixed or determinable dates that is recognized as an asset in the creditor's statement of acquired loan position. Financing Receivables, Period Past Due [Axis] Financing Receivables, Period Past Due [Axis] Financing Receivables, Period Past Due [Domain] Financing Receivables, Period Past Due [Domain] 30 – 59 Days Past Due Financing Receivables, 30 to 59 Days Past Due [Member] 60 – 89 Days Past Due Financing Receivables, 60 to 89 Days Past Due [Member] Over 89 Days Past Due Financing Receivables, Equal to Greater than 90 Days Past Due [Member] Class of Financing Receivable, Type [Axis] Class of Financing Receivable, Type [Axis] Class of Financing Receivable, Type [Domain] Class of Financing Receivable, Type [Domain] Administratively Delinquent Administratively Delinquent [Member] Information pertaining to loans and leases classified as administratively delinquent. Financing Receivable, Recorded Investment, Past Due [Line Items] Financing Receivable, Recorded Investment, Past Due [Line Items] Loans and leases, past due Financing Receivable, Recorded Investment, Past Due Loans and leases, current Financing Receivable, Recorded Investment, Current Loans and leases, accruing Loans and leases, accruing Represents the amount of accruing loans and leases. Non-accrual loans and leases Financing Receivable, Recorded Investment, Nonaccrual Status Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Table] Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Table] Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items] Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items] Contractually required principal and interest payments Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Acquired During Period, Contractually Required Payments Receivable at Acquisition Contractual cash flows not expected to be collected (nonaccretable difference) Certain Loans Acquired in Transfer, Nonaccretable Difference Cash flows expected to be collected Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Acquired During Period, Cash Flows Expected to be Collected at Acquisition Interest component of expected cash flows (accretable yield) Certain Loans Acquired in Transfer, Accretable Yield Fair value of loans acquired with deterioration of credit quality Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Acquired During Period, at Acquisition, at Fair Value Basis of Presentation Business Description and Basis of Presentation [Text Block] Interest-bearing demand Interest-bearing Domestic Deposit, Checking Money market Interest-bearing Domestic Deposit, Money Market Savings Interest-bearing Domestic Deposit, Savings Retail time deposits Retail time deposits The amount of retail time deposits. Wholesale non-maturity deposits Wholesale non-maturity deposits Represents the amount of wholesale non-maturity deposits. Wholesale time deposits Wholesale time deposits Represents the amount of wholesale time deposits. Total interest-bearing deposits Noninterest-bearing deposits Goodwill and Intangibles Assets Goodwill and Intangible Assets Disclosure [Text Block] Goodwill impairment Goodwill, Impairment Loss Impairment of intangibles Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill) Long-term Federal Home Loan Bank Advances [Abstract] Federal Home Loan Bank, Advances [Table] Federal Home Loan Bank, Advances [Table] Short-term FHLB advances Federal Home Loan Bank Advances [Member] Federal Home Loan Bank, Advances [Line Items] Federal Home Loan Bank, Advances [Line Items] Within one year Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months Over one year through five years Over one year through five years Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing over the next five fiscal years. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Total Other Long-term Debt Schedule of Indefinite-Lived Intangible Assets [Table] Schedule of Indefinite-Lived Intangible Assets [Table] Reporting Unit [Axis] Reporting Unit [Axis] Reporting Unit [Domain] Reporting Unit [Domain] Goodwill – Wealth Wealth Management [Member] Component of an entity that usually provides financial, operational and administrative support and is considered an wealth segment. Goodwill – Banking Banking [Member] Component of an entity that usually provides financial, operational and administrative support and is considered an banking segment. Goodwill – Insurance Insurance [Member] Segment information. Core deposit intangible Customer relationships Non-compete agreements Trade name Favorable lease assets Indefinite-lived Intangible Assets [Axis] Indefinite-lived Intangible Assets [Axis] Indefinite-lived Intangible Assets, Major Class Name [Domain] Indefinite-lived Intangible Assets, Major Class Name [Domain] Domain Name Domain Name [Member] String of typographic characters used to describe the location of a specific individual, business, computer, or piece of information online. Formally known as the Uniform Resource Locator or URL, it is often considered to be the address of a certain World Wide Web site. Indefinite-lived Intangible Assets [Line Items] Indefinite-lived Intangible Assets [Line Items] Additions Goodwill, Acquired During Period Adjustments Goodwill, Translation and Purchase Accounting Adjustments Finite-lived Intangible Assets [Roll Forward] Finite-lived Intangible Assets [Roll Forward] Balance December 31, 2017 Finite-Lived Intangible Assets, Net Additions Finite-lived Intangible Assets Acquired Intangible assets amortization Balance September 30, 2018 Intangible asset amortization period (Year) Finite-Lived Intangible Asset, Useful Life Indefinite-lived Intangible Assets [Roll Forward] Indefinite-lived Intangible Assets [Roll Forward] Indefinite-lived intangible assets Indefinite-lived Intangible Assets (Excluding Goodwill) Indefinite-lived intangible assets acquired Indefinite-lived Intangible Assets Acquired Indefinite-lived intangible assets Total Intangible Assets Additions Intangible assets amortization Total Intangible Assets Total Goodwill and Intangible Assets, beginning balance Intangible Assets (Including Goodwill) Intangible Assets (Including Goodwill) Intangible Assets (Including Goodwill) Acquired Intangible Assets (Including Goodwill) Acquired Intangible Assets (Including Goodwill) Acquired Grand Total adjustments Grand Total Adjustments The amount of adjustments to goodwill and intangible assets during the period. Intangible assets amortization Goodwill And Intangible Asset Amortization The amount of goodwill and intangible asset amortization during the period. Total Goodwill and Intangible Assets, ending balance Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Retained Earnings Retained Earnings [Member] Accumulated Other Comprehensive Loss Statement [Line Items] Statement [Line Items] Other comprehensive loss, tax expense Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent Short-term Debt, Type [Axis] Short-term Debt, Type [Axis] Short-term Debt, Type [Domain] Short-term Debt, Type [Domain] Overnight Federal Funds Overnight Federal Funds [Member] Type of short-term borrowings. Federal Reserve Discount Window Federal Reserve Discount Window [Member] Type of borrowing. Long-term FHLB advances Federal Home Loan Bank stock Federal Home Loan Bank maximum borrowing capacity Federal Home Loan Bank, Advances, General Debt Obligations, Maximum Amount Available Federal Home Loan Bank, advances, amount available Federal Home Loan Bank, Advances, General Debt Obligations, Amount of Available, Unused Funds Debt Securities, Available-for-sale [Table] Debt Securities, Available-for-sale [Table] Obligations of the U.S. government and agencies US Government Agencies Debt Securities [Member] Obligations of state and political subdivisions US States and Political Subdivisions Debt Securities [Member] Collateralized mortgage obligations Collateralized Mortgage Obligations [Member] Other investment securities Other Debt Obligations [Member] Debt Securities, Available-for-sale [Line Items] Debt Securities, Available-for-sale [Line Items] Fair Value Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract] Securities available for sale, less than 12 months, fair value Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months Securities available for sale, 12 months or longer, fair value Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer Securities available for sale, fair value Debt Securities, Available-for-sale, Unrealized Loss Position Unrealized Losses Debt Securities, Available-for-sale, Unrealized Loss Position [Abstract] Securities available for sale, less than 12 months, unrealized losses Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Securities available for sale, 12 months or longer, unrealized losses Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Securities available for sale, unrealized losses Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss Schedule of Accumulated Other Comprehensive Income (Loss) Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Reclassification out of Accumulated Other Comprehensive Income Reclassification out of Accumulated Other Comprehensive Income [Table Text Block] Advertising bmtc_BusinessCombinationIntegrationRelatedCostsAdvertising The adverting costs incurred to effect a business combination which have been expensed during the period. Employee Benefits bmtc_BusinessCombinationIntergrationRelatedCostsEmployeeBenefits The employee benefit costs incurred to effect a business combination which have been expensed during the period. Occupancy and bank premises bmtc_BusinessCombinationIntegrationRelatedCostsOccupancyAndBankPremises The occupancy and bank premises costs incurred to effect a business combination which have been expensed during the period. Furniture, fixtures, and equipment bmtc_BusinessCombinationIntegrationRelatedCostsFurnitureFixturesAndEquipment The furniture, fixture and equipment costs incurred to effect a business combination which have been expensed during the period. Information technology bmtc_BusinessCombinationIntegrationRelatedCostsInformationTechnology The information and technology incurred to the effect a business combination which have been expensed during the period. Professional fees bmtc_BusinessCombinationIntegrationRelatedCostsProfessionalFees The professional fees incurred to effect a business combination which have been expensed during the period. Salaries and wages bmtc_BusinessCombinationIntegrationRelatedCostsSalariesAndWages The salaries and wages incurred to effect a business combination which have been expensed during the period. Other bmtc_BusinessCombinationIntegrationRelatedCostsOther The other costs incurred to effect a business combination which have been expensed during the period. Total due diligence, merger-related and merger integration expenses Business Combination, Integration Related Costs Performance Stock Awards Performance Stock Awards [Member] Information pertaining to performance stock awards. Number of Shares Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Balance (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Forfeited (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Balance (in shares) Weighted Average Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Balance, weighted average grant date fair value (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Granted, weighted average grant date fair value (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Vested, weighted average grant date fair value (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Forfeited, weighted average grant date fair value (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Balance, weighted average grant date fair value (in dollars per share) Schedule of Impaired Financing Receivable [Table] Schedule of Impaired Financing Receivable [Table] Impaired Loans Without Related Allowance Impaired Loans Without Related Allowance [Member] The information of investment and principal balance of impaired loans. Financing Receivable, Impaired [Line Items] Financing Receivable, Impaired [Line Items] Impaired loans with related allowance, recorded investment Impaired Financing Receivable, with Related Allowance, Recorded Investment Impaired loans with related allowance, principal balance Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance Impaired loans, related allowance Impaired Financing Receivable, Related Allowance Impaired loans with related allowance, average principal balance Impaired Financing Receivable, with Related Allowance, Average Recorded Investment Impaired loans with related allowance, interest income recognized Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method Impaired loans without related allowance, recorded investment Impaired Financing Receivable, with No Related Allowance, Recorded Investment Impaired loans without related allowance, principal balance Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance Impaired loans without related allowance, average principal balance Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment Impaired loans without related allowance, interest income recognized Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method Impaired loans, recorded investment Impaired Financing Receivable, Recorded Investment Impaired loans, principal balance Impaired Financing Receivable, Unpaid Principal Balance Impaired loans, related allowance Impaired loans, average principal balance Impaired Financing Receivable, Average Recorded Investment Impaired loans, interest income recognized Impaired Financing Receivable, Interest Income, Accrual Method Loss Contingencies [Table] Loss Contingencies [Table] Commitments to Extend Credit Commitments to Extend Credit [Member] Investment Type [Axis] Investment Type [Axis] Investments [Domain] Investments [Domain] Standby Letters of Credit Standby Letters of Credit [Member] Loss Contingencies [Line Items] Loss Contingencies [Line Items] Commitments and obligations, liability outstanding Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Liability Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust [Abstract] Investment Holdings [Table] Investment Holdings [Table] Investment [Axis] Investment [Axis] Investment [Domain] Investment [Domain] Royal Bancshares Capital Trust II Royal Bancshares Capital Trust II [Member] Represents information pertaining to Royal Bancshares Capital Trust II. Royal Bancshares Capital Trust I and II Royal Bancshares Capital Trust I and II [Member] Represents the information pertaining to Royal Bancshares Capital Trust I and II. Royal Bancshares Capital Trust I Royal Bancshares Capital Trust I [Member] Represents the information pertaining to Royal Bancshares Capital Trust I. Royal Bancshares of Pennsylvania, Inc. Royal Bancshares of Pennsylvania, Inc. [Member] Represents information pertaining to the company, Royal Bancshares of Pennsylvania, Inc. Counterparty Name [Axis] Counterparty Name [Axis] Counterparty Name [Domain] Counterparty Name [Domain] Junior Subordinated Debentures, RBPI Merger Junior Subordinated Debentures, RBPI Merger [Member] Represents the junior subordinated debentures in connection with RBPI Merger. Junior Subordinated Debt Junior Subordinated Debt [Member] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Investment Holdings [Line Items] Investment Holdings [Line Items] Common securities of Trust I and Trust II owned Coupon rate (as a percent) Debt Instrument, Interest Rate, Effective Percentage Capital securities issued, amount bmtc_TrustCapitalSecuritiesIssued The amount of capital securities initially bearing fixed and/or fixed/floating interest rates corresponding to the debt securities held by a trust to an unaffiliated investment vehicle. Common securities issued, amount bmtc_TrustCommonSecuritiesIssued The amount of common securities bearing fixed and or fixed/floating interest rates corresponding to the debt securities held by a trust. Business Acquisition, Pro Forma Information, Nonrecurring Adjustments [Table] Business Acquisition, Pro Forma Information, Nonrecurring Adjustments [Table] Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Pro Forma Pro Forma [Member] Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items] Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items] Total interest income Total interest expense Provision for loan and lease losses Provision for Loan, Lease, and Other Losses Total noninterest income Total non-interest expense Income tax expense Weighted-average basic shares outstanding (in shares) Basic earnings per share (in dollars per share) Diluted earnings per share (in dollars per share) Revenue from Contract with Customer [Abstract] Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] Real estate loans Real Estate Portfolio Segment [Member] Portfolio segment of the company's total financing receivables related to real estate financing receivables. Home equity loan, number of contracts Financing Receivable, Modifications, Subsequent Default, Number of Contracts Home equity line of credit principal balance Financing Receivable, Modifications, Subsequent Default, Recorded Investment Balance at period-end Maximum amount outstanding at any month end Short-term Debt, Maximum Month-end Outstanding Amount Average balance outstanding during the period Short-term Debt, Average Outstanding Amount Short-term debt, weighted average interest rate at period end (as a percent) Short-term Debt, Weighted Average Interest Rate, at Point in Time Short-term debt, weighted average interest rate aid during the period (as a percent) Paid during the period Weighted Average Interest Rate Paid During Period On Short Term Borrowings. Transfers and Servicing [Abstract] Servicing Asset at Amortized Cost Servicing Asset at Amortized Cost [Table Text Block] Schedule of Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets Schedule of Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets [Table Text Block] Statement of Cash Flows [Abstract] Operating activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Net income attributable to Bryn Mawr Bank Corporation Adjustments to reconcile net income to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation of fixed assets Depreciation, Depletion and Amortization Net amortization of investment premiums and discounts Depreciation, Depletion and Amortization, Nonproduction Net gain on sale of investment securities available for sale Net gain on sale of loans Stock based compensation Share-based Compensation Amortization and net impairment of mortgage servicing rights Amortization and net impairment of mortgage servicing rights The amortization and net impairment of mortgage servicing rights. Net accretion of fair value adjustments Net accretion of fair value adjustments Represents the amount of net accretion of fair value adjustments. Impairment of OREO and other repossessed assets Impairment of Real Estate Net (gain) loss on sale of OREO Increase (Decrease) in Other Operating Assets and Liabilities, Net Net increase in cash surrender value of bank owned life insurance (BOLI) Bank Owned Life Insurance Income Other, net Increase (Decrease) in Operating Capital Loans originated for resale Payments for Origination of Mortgage Loans Held-for-sale Proceeds from loans sold Proceeds from Sale of Mortgage Loans Held-for-sale Provision for deferred income taxes Deferred Income Tax Expense (Benefit) Change in income taxes payable/receivable, net Income Tax Credits and Adjustments Change in accrued interest receivable Increase (Decrease) in Accrued Interest Receivable, Net Change in accrued interest payable Increase (Decrease) in Interest Payable, Net Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Purchases of investment securities available for sale Payments to Acquire Available-for-sale Securities Purchases of investment securities held to maturity Payments to Acquire Held-to-maturity Securities Proceeds from maturity and paydowns of investment securities available for sale Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-sale Proceeds from maturity and paydowns of investment securities held to maturity Proceeds from Maturities, Prepayments and Calls of Held-to-maturity Securities Proceeds from sale of investment securities available for sale Proceeds from Sale of Available-for-sale Securities Net change in FHLB stock Payments for (Proceeds from) Federal Home Loan Bank Stock Proceeds from calls of investment securities Proceeds from Maturities, Prepayments and Calls of Other Investments Net change in other investments Payments for (Proceeds from) Other Investing Activities Purchase of domain name Payments to Acquire Intangible Assets Purchase of portfolio loans and leases Payments for (Proceeds from) Other Loans and Leases Net portfolio loan and lease originations Proceeds From (Payments For) Loan Originations Proceeds From (Payments For) Loan Originations Purchases of premises and equipment Payments to Acquire Property, Plant, and Equipment Acquisitions, net of cash acquired Payments to Acquire Businesses, Net of Cash Acquired Capitalize costs to OREO Payments to Acquire Other Real Estate Proceeds from sale of OREO Proceeds from Sale of Other Real Estate Net cash provided by (used in) investing activities Net Cash Provided by (Used in) Investing Activities Financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Change in deposits Increase (Decrease) in Deposits Change in short-term borrowings Proceeds from (Repayments of) Short-term Debt Dividends paid Payments of Dividends Change in long-term FHLB advances and other borrowings Payments of FHLBank Borrowings, Financing Activities Payment of contingent consideration for business combinations Payment for Contingent Consideration Liability, Financing Activities Cash payments to taxing authorities on employees' behalf from shares withheld from stock-based compensation Payments Related to Tax Withholding for Share-based Compensation Net proceeds from sale of treasury stock for deferred compensation plans Proceeds from Issuance or Sale of Equity Purchase of treasury stock for deferred compensation plans Payments for Repurchase of Equity Repurchase of warrants from U.S. Treasury Payments for Repurchase of Warrants Net purchase of treasury stock through publicly announced plans Payments for Repurchase of Common Stock Proceeds from exercise of stock options Proceeds from Stock Options Exercised Net cash (used in) provided by financing activities Net Cash Provided by (Used in) Financing Activities Change in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and cash equivalents at beginning of period Cash and cash equivalents at end of period Supplemental cash flow information: Supplemental Cash Flow Information [Abstract] Income taxes Income Taxes Paid, Net Interest Interest Paid, Excluding Capitalized Interest, Operating Activities Non-cash information: Noncash Investing and Financing Items [Abstract] Change in other comprehensive loss Change in deferred tax due to change in comprehensive income Change in deferred tax due to change in comprehensive income Represents the amount of change in deferred taxes due to change in other comprehensive income (loss). Transfer of loans to OREO and repossessed assets Real Estate Owned, Transfer from Real Estate Owned Acquisition of noncash assets and liabilities: Noncash or Part Noncash Acquisition, Value of Assets Acquired [Abstract] Assets acquired Noncash or Part Noncash Acquisition, Value of Assets Acquired Liabilities assumed Noncash or Part Noncash Acquisition, Value of Liabilities Assumed Short-Term Borrowings and Long-Term FHLB Advances Federal Home Loan Bank Advances, Disclosure [Text Block] Other comprehensive (loss) income: Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, after Tax [Abstract] Net unrealized (losses) gains arising during the period, net of tax (benefit) expense of $(616), $105, $(2,337), and $535, respectively Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, after Tax Reclassification adjustment for net (gain) on sale realized in net income, net of tax (expense) of $0, $(25), $(1), and $(25), respectively Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax Reclassification adjustment for net (gain) realized on transfer of investment securities available for sale to trading, net of tax (expense) benefit of $0, $0, $(88), and $0, respectively Other Comprehensive Income (Loss), Reclassification Adjustment From Aoci For Investment Transferred From Available-for-sale To Trading, After Tax Amount, after tax, of reclassification adjustment from accumulated other comprehensive income (loss) for unrealized gain (loss) of investment classified as available-for-sale transferred to trading. Unrealized investment (losses) gains, net of tax (benefit) expense of $(616), $80, $(2,426), and $510, respectively Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, after Tax Net change in unfunded pension liability: Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax [Abstract] Change in unfunded pension liability related to unrealized loss, prior service cost and transition obligation, net of tax expense of $28, $9, $37, and $34, respectively Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), after Tax Total other comprehensive (loss) income Total comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Reclassification out of Accumulated Other Comprehensive Income [Table] Reclassification out of Accumulated Other Comprehensive Income [Table] Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification out of Accumulated Other Comprehensive Income [Domain] Amount Reclassified from Accumulated Other Comprehensive Loss Reclassification out of Accumulated Other Comprehensive Income [Member] Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items] Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items] Other operating expenses Realization of gain on sale of investment securities available for sale Debt and Equity Securities, Gain (Loss) Income before income taxes Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] Banking Wealth Management Product and Service [Axis] Product and Service [Axis] Product and Service [Domain] Product and Service [Domain] Fees for wealth management services Asset Management [Member] Service charges on deposit accounts Deposit Account [Member] Merchant Interchange Fees, Safe Deposit Box Rentals, and Rent Income Merchant Interchange Fees, Safe Deposit Box Rentals, and Rent Income [Member] Represents merchant interchange fees, safe deposit box rentals, and rent income. Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Revenue Revenue from Contract with Customer, Including Assessed Tax Insurance commissions Loan servicing and other fees Net gain on sale of loans Net gain on sale of investment securities available for sale Dividends on FHLB and FRB stock Other operating income Schedule of Short-term Debt [Table] Schedule of Short-term Debt [Table] Repurchase agreements – commercial customers Repurchase Agreements Commercial Customers [Member] Information pertaining to repurchase agreements from commercial customers. Short-term Debt [Line Items] Short-term Debt [Line Items] Summary of Deposits Deposit Liabilities, Type [Table Text Block] Proceeds from exercise of stock options Related tax benefit recognized Employee Service Share-based Compensation, Tax Benefit from Exercise of Stock Options Net proceeds of options exercised Net proceeds of options exercised The cash inflow from stock options exercised including excess tax benefit. Intrinsic value of options exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value Derivative Instruments and Hedging Activities Disclosures [Table] Derivative Instruments and Hedging Activities Disclosures [Table] Hedging Designation [Axis] Hedging Designation [Axis] Hedging Designation [Domain] Hedging Designation [Domain] Not Designated as Hedging Instrument Not Designated as Hedging Instrument [Member] Customer derivatives – interest rate swaps Derivative Instruments and Hedging Activities Disclosures [Line Items] Derivative Instruments and Hedging Activities Disclosures [Line Items] Derivative Asset [Abstract] Derivative Asset [Abstract] Notional Amount Derivative Asset, Notional Amount Fair Value Derivative Asset, Fair Value, Amount Not Offset Against Collateral Derivative Liability [Abstract] Derivative Liability [Abstract] Notional Amount Derivative Liability, Notional Amount Fair Value Derivative Liability, Fair Value, Amount Not Offset Against Collateral Revenue from Contracts with Customers Revenue from Contract with Customer [Text Block] Common Stock Common Stock [Member] Paid-in Capital Additional Paid-in Capital [Member] Treasury Stock Treasury Stock [Member] Noncontrolling Interest Noncontrolling Interest [Member] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Beginning balance (in shares) Beginning balance Net income attributable to noncontrolling interest Dividends paid or accrued, $0.69 per share Dividends, Common Stock, Cash Other comprehensive loss, net of tax benefit of $2,389 Stock based compensation Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Retirement of treasury stock (in shares) Treasury Stock, Shares, Retired Retirement of treasury stock Treasury Stock, Retired, Cost Method, Amount Net purchase of treasury stock from stock awards for statutory tax withholdings Treasury Stock, Value, Acquired, Cost Method Net treasury stock activity for deferred compensation trusts Net sale of treasury stock for deferred compensation trusts Equity impact of the cost of common stock that were sold from stock awards and deferred compensation plans during the period. Repurchase of warrants from U.S. Treasury Repurchase Of Warrants Amount of decrease in additional paid in capital (APIC) resulting from the repurchase of warrants. Common stock issued through share-based awards and options exercises (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Common stock issued through share-based awards and options exercises Stock Issued During Period, Value, Stock Options Exercised Shares issued in acquisitions (in shares) Stock Issued During Period, Shares, Acquisitions Shares issued in acquisitions Stock Issued During Period, Value, Acquisitions Ending balance (in shares) Ending balance Available-for-sale Securities Available-for-sale Securities [Table Text Block] Summary of Available-for-sale Debt Securities, Unrealized Loss Position, Fair Value Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value [Table Text Block] Investments Classified by Contractual Maturity Date Investments Classified by Contractual Maturity Date [Table Text Block] Summary of Held-to-maturity Debt Securities Debt Securities, Held-to-maturity [Table Text Block] Summary of Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value [Table Text Block] Tabular disclosure of fair value of investments in debt and equity securities in an unrealized loss position categorized as held-to-maturity. Accumulated Other Comprehensive (Loss) Income Comprehensive Income (Loss) Note [Text Block] Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Net interest income Service charges on deposit accounts Net gain on sale of investment securities available for sale Debt Securities, Available-for-sale, Gain (Loss) Net gain on sale of OREO Other operating income bmtc_OtherOperatingIncomeIncludingDividendsOnFhlbAndFrbStock The amount of other operating income including dividends on FHLB and FRB stock. Other operating expenses Other Cost and Expense, Operating Segment profit Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Intersegment (revenues) expenses Revenues Pre-tax segment profit after eliminations Pre-tax segment profit after eliminations Represents the amount of segment reporting informations profit (loss). % of segment pre-tax profit after eliminations % of segment pre-tax profit after eliminations Represents the percentage of segment pretax profit after eliminations. Segment assets Assets under management, administration, supervision and brokerage Assets under Management, Carrying Amount Schedules of Recognized Identified Assets Acquired and Liabilities Assumed Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block] Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustments Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustments [Table Text Block] The tabular disclosure of adjustments to a business combination for which the initial accounting is incomplete. Summary of Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Table Text Block] Business Acquisition, Pro Forma Information Business Acquisition, Pro Forma Information [Table Text Block] Summary of Integration Related Costs Business Combination Integration Related Costs [Table Text Block] The tabular disclosure for the integration costs associated with business combinations. Junior Subordinated Debentures Junior Subordinated Borrowings Disclosure [Text Block] The entire disclosure for borrowings under junior subordinated debt agreements that qualify as available in computing net capital under SEC's uniform net capital rule, including restrictive covenants, collateral, interest rates and due dates, amounts due by date and amount owed in total. Bullet maturity – fixed rate Bullet Maturity [Member] Information pertaining to bullet maturity. Convertible-fixed Convertible-fixed [Member] Information pertaining to the convertible-fixed rate. Debt Instrument, Interest Rate by Interest Type [Axis] Debt Instrument, Interest Rate by Interest Type [Axis] Information by type of interest rate. Debt Instrument Interest Rate By Interest Type [Domain] Debt Instrument Interest Rate By Interest Type [Domain] Fixed Rate Fixed Rate [Member] Information pertaining to the fixed rate. Weighted average rate Weighted Average [Member] Federal Home Loan Bank, advances, interest rate at period end Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Interest Rate at Period End Other long-term debt U.S. Treasury securities US Treasury Securities [Member] Amortized Cost Gross Unrealized Gains Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax Gross Unrealized Losses Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax Fair Value Options outstanding (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Weighted average exercise price, options outstanding (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Aggregate intrinsic value, options outstanding Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Weighted average contractual term, options outstanding (Year) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Exercisable options (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Weighted average exercise price, exercisable options (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Aggregate intrinsic value, exercisable options Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value Weighted average contractual term, exercisable options (Year) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Total loans and leases Loans Receivable, Net Loans with fixed rates Loans Receivable with Fixed Rates of Interest Loans with adjustable or floating rates Loans Receivable with Variable Rates of Interest Total loans and leases Net deferred loan origination fees included in the above loan table Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums Stockholders' Equity Note [Abstract] Shareholders' Equity Stockholders' Equity Note Disclosure [Text Block] Mutual funds with no stated maturity Mutual Funds [Member] Information pertaining to mutual funds. Amortized Cost Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost [Abstract] Available for sale securities, due in one year or less, amortized cost Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Amortized Cost Available for sale securities, due after one year through five years, amortized cost Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Amortized Cost Available for sale securities, due after five years through ten years, amortized cost Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Amortized Cost Available for sale securities, due after ten years, amortized cost Debt Securities, Available-for-sale, Allocated and Single Maturity Date, Maturity, after 10 Years, Amortized Cost Available for sale securities, subtotal, amortized cost Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost Available for sale securities, no stated maturity, amortized cost Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Amortized Cost Fair Value Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling Maturity, Fair Value [Abstract] Available for sale securities, due in one year or less, fair value Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value Available for sale securities, due after one year through five years, fair value Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Fair Value Available for sale securities, due after five years through ten years, fair value Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Fair Value Available for sale securities, due after ten years, fair value Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after 10 Years, Fair Value Available for sale securities, subtotal, fair value Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value Available for sale securities, no stated maturity, fair value Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Fair Value Fair Value Denominator for basic earnings per share – weighted average shares outstanding Effect of dilutive common shares Antidilutive shares excluded from computation of average dilutive earnings per share Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Acquired loans, outstanding principal Acquired loans, outstanding principal Amount of outstanding principal balance of loans acquired. Acquired loans, remaining loan mark Acquired Loans, Remaining Loan Mark Acquired Loans, Remaining Loan Mark Acquired loans, recorded investment Acquired loans, recorded investment Amount of investment of financing receivables. Schedule of Servicing Assets at Fair Value [Table] Schedule of Servicing Assets at Fair Value [Table] Residential mortgages Residential Mortgage [Member] Servicing Assets at Fair Value [Line Items] Servicing Assets at Fair Value [Line Items] Fair value Servicing Asset at Amortized Cost, Fair Value Weighted average life (in years) Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Weighted Average Life Prepayment speeds (constant prepayment rate) Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Prepayment Speed 10% adverse change Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets, Impact of 10 Percent Adverse Change in Prepayment Speed 20% adverse change Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets, Impact of 20 Percent Adverse Change in Prepayment Speed Discount rate (as a percent) Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Discount Rate 10% adverse change Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets, Impact of 10 Percent Adverse Change in Discount Rate 20% adverse change Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets, Impact of 20 Percent Adverse Change in Discount Rate Shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Options outstanding (in shares) Forfeited (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period Expired (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period Exercised (in shares) Options outstanding (in shares) Weighted Average Exercise Price Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Options outstanding, weighted average exercise price (in dollars per share) Forfeited, weighted average exercise price (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price Expired, weighted average exercise price (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Expirations in Period, Weighted Average Exercise Price Exercised, weighted average exercise price (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Options outstanding, weighted average exercise price (in dollars per share) Weighted Average Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Options outstanding, weighted average grant date fair value (in dollars per share) Share Based Compensation Arrangement By Share Based Payment Award, Options Outstanding, Weighted Average Fair Value Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Fair Value. Forfeited, weighted average grant date fair value (in dollars per share) Share Based Compensation Arrangement By Share Based Payment Award, Options Forfeited In Period, Weighted Average Grant Date Fair Value Share Based Compensation Arrangement By Share Based Payment Award Options Forfeited In Period Weighted Average Grant Date Fair Value. Expired, weighted average grant date fair value (in dollars per share) Share Based Compensation Arrangement By Share Based Payment Award, Options Expirations In Period, Weighted Average Grant Date Fair Value Share Based Compensation Arrangement By Share Based Payment Award Options Expirations In Period Weighted Average Grant Date Fair Value. Exercised, weighted average grant date fair value (in dollars per share) Share Based Compensation Arrangement By Share Based Payment Award, Options Exercises In Period, Weighted Average Fair Value Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Fair Value. Options outstanding, weighted average grant date fair value (in dollars per share) Purchased credit impaired became non-performing subsequent to acquisition bmtc_LoansAndLeasesReceivablePurchasedCreditImpairedBecameNonperformingSubsequentToAcquisition The amount of purchased credit impaired became non-performing subsequent to acquisition in loans and leases receivable. Derivative Instruments and Hedging Activities Derivative Instruments and Hedging Activities Disclosure [Text Block] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair Value, Measurements, Recurring Fair Value, Measurements, Recurring [Member] Fair Value, Measurements, Nonrecurring Fair Value, Measurements, Nonrecurring [Member] Asset Class [Axis] Asset Class [Axis] Asset Class [Domain] Asset Class [Domain] Mortgage-backed securities Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Investment securities trading Debt Securities, Trading Derivatives MSRs Servicing Asset at Fair Value, Amount Impaired loans and leases Impaired loans and leases The fair value of impaired loans and leases. OREO OREO The fair value of other real estate owned. Earnings per Common Share Earnings Per Share [Text Block] Financial Instrument Performance Status [Axis] Financial Instrument Performance Status [Axis] Financial Instrument Performance Status [Domain] Financial Instrument Performance Status [Domain] Performing Financial Instruments Performing Financial Instruments [Member] Nonperforming Financial Instruments Nonperforming Financial Instruments [Member] Performing and Non-performing Performing and Non-performing [Member] Amounts due the Company for loans secured by the collateral of specified non-performing and performing loans. Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event Subsequent Event [Member] RSU's and PSU's RSU's and PSU's [Member] Awards classified and restricted stock units and performance units. Share Repurchase Program [Axis] Share Repurchase Program [Axis] Share Repurchase Program [Domain] Share Repurchase Program [Domain] The 2015 Program The 2015 Program [Member] Information regarding the 2015 stock repurchase program. Class of Stock [Line Items] Class of Stock [Line Items] Dividends declared per share (in dollars per share) Common Stock, Dividends, Per Share, Declared Dividends paid (in dollars per share) Common Stock, Dividends, Per Share, Cash Paid Total dividends Dividends, Common Stock Shelf registration, shares registered bmtc_ShelfRegistrationShares Represents the number of shares in shelf registration. Maximum investment under stock purchase and dividend reinvestment plan bmtc_MaximumInvestmentUnderStockPurchaseAndDividendReinvestmentPlan Represents the maximum amount of investment under the Stock Purchase and Dividend Retirement Plan. Shares issued pursuant to exercise of stock options (in shares) Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures Stock issued, increase in shareholders' equity Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures Stock repurchase program, number of shares authorized to be repurchased Stock Repurchase Program, Number of Shares Authorized to be Repurchased Stock repurchase program, authorized amount Stock Repurchase Program, Authorized Amount Shares repurchased during period Stock Repurchased During Period, Shares Shares remaining authorized for repurchase Stock Repurchase Program, Remaining Authorized Repurchase Amount Schedule of Short-term Debt Schedule of Short-term Debt [Table Text Block] Schedule of Additional Information on Short Term Borrowings Schedule of Additional Information on Short Term Borrowings [TableText Block] Tabular disclosure of additional information on short-term borrowings. Schedule of Maturities of Long-term Debt Schedule of Maturities of Long-term Debt [Table Text Block] Schedule of Federal Home Loan Bank Advances and Other Borrowings Maturities Schedule of Federal Home Loan Bank Advances and Other Borrowings Maturities [Table Text Block] Tabular disclosure of Federal Home Loan Bank Advances and other borrowings maturities. Outstanding principal balance Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Outstanding Balance Carrying amount Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Carrying Amount, Net Purchased credit impaired loans without estimate of expected cash flows recorded investment bmtc_PurchasedCreditImpairedLoansWithoutEstimateOfExpectedCashFlowsRecordedInvestment Represents the amount of purchased credit impaired loans without estimate of expected cash flows recorded investment. Securities pledged as collateral Debt Securities, Available-for-sale, Restricted Investment securities held in trading accounts Available for sale securities reclassified to trading Debt Securities, Available-for-sale, Transfer to Trading, Amount Debt Securities, Available-for-sale, Transfer to Trading, Amount Fair Value Measurement Fair Value Disclosures [Text Block] Sensitivity percent, adverse change in assumption, low Sensitivity Analysis Of Fair Value Of Interests Continued To Be Held By Transfer Or Servicing Assets Or Liabilities Percent Adverse Change In Assumption Low Represents the lower range of percentage of adverse change in assumption used in sensitivity analysis of fair value of interests continued to be held by transferor servicing assets or liabilities. Sensitivity percent, adverse change in assumption, high Sensitivity Analysis Of Fair Value Of Interests Continued To Be Held By Transferor Servicing Assets Or Liabilities Percent Adverse Change In Assumption High Represents the upper range of percentage of adverse change in assumption used in sensitivity analysis of fair value of interests continued to be held by transferor servicing assets or liabilities. Loans and Leases Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Segment Information Segment Reporting Disclosure [Text Block] Servicing Asset at Fair Value, Amount [Roll Forward] Servicing Asset at Fair Value, Amount [Roll Forward] Balance, beginning of period Additions Servicing Asset at Amortized Cost, Additions Amortization Servicing Asset at Amortized Cost, Amortization Recovery / (Impairment) Servicing Asset at Amortized Cost, Increase (Decrease) for Valuation Allowance Adjustment Balance, end of period Residential mortgage loans serviced for others Residential mortgage loans serviced for others Residential Mortgage Loans Serviced for Others. Schedule of Derivative Instruments in Statement of Financial Position, Fair Value Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] Income Tax Disclosure [Abstract] Accrued interest and penalties Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued Schedule of Financing Receivable, Troubled Debt Restructurings [Table] Schedule of Financing Receivable, Troubled Debt Restructurings [Table] Loan Restructuring Modification [Axis] Loan Restructuring Modification [Axis] Loan Restructuring Modification [Domain] Loan Restructuring Modification [Domain] Loan Term Extension Extended Maturity [Member] Interest Rate Change and Term Extension Interest Rate Change And Term Extension [Member] Interest Rate Change And Term Extension [Member] Interest Rate Change and/or Interest-Only Period Interest Rate Change And/Or Interest-Only Period [Member] Interest Rate Change And/Or Interest-Only Period [Member] Contractual Payment Reduction (Leases only) Contractual Payment Reduction (Leases only) [Member] Loan modification for a contractual payment reduction for leases only. Temporary Payment Deferral Payment Deferral [Member] Financing Receivable, Modifications [Line Items] Financing Receivable, Modifications [Line Items] Troubled debt restructurings Financing Receivable, Modifications, Recorded Investment Number of contracts Financing Receivable, Modifications, Number of Contracts Pre-Modification Outstanding Recorded Investment Financing Receivable, Modifications, Pre-Modification Recorded Investment Post-Modification Outstanding Recorded Investment Financing Receivable, Modifications, Post-Modification Recorded Investment Recent Accounting Pronouncements New Accounting Pronouncements and Changes in Accounting Principles [Text Block] Accounting for Uncertainty in Income Taxes Income Tax Disclosure [Text Block] Mortgage Servicing Rights Transfers and Servicing of Financial Assets [Text Block] Amortized Cost Fair Value Internal Credit Assessment [Axis] Internal Credit Assessment [Axis] Internal Credit Assessment [Domain] Internal Credit Assessment [Domain] Pass Pass [Member] Special Mention Special Mention [Member] Substandard Substandard [Member] Doubtful Doubtful [Member] Pass, Special Mention and Substandard Pass, Special Mention and Substandard [Member] Type of pass, special mention and substandard. Fair Value of Financial Instruments Fair Value Measurement and Measurement Inputs, Recurring and Nonrecurring [Text Block] Summary of Fair Value by Balance Sheet Grouping Fair Value, by Balance Sheet Grouping [Table Text Block]