Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block] Earnings Per Share [Abstract] Schedule of Earnings Per Share, Basic and Diluted [Table] Schedule of Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Table] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Liberty Property Limited Partnership [Member] Liberty Property Limited Partnership [Member] Limited Partnership. Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Common Units [Member] Common Class B [Member] Earnings Per Unit, Basic and Diluted [Line Items] Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items] Income (Numerator) [Abstract] Net Income (Loss) Available to Common Stockholders, Basic [Abstract] Income from continuing operations net of noncontrolling interest - consolidated joint ventures Income (Loss) from Continuing Operations Attributable to Parent Less: Preferred unit distributions Preferred Stock Dividends, Income Statement Impact Net income available to common shareholders Net Income (Loss) Available to Common Stockholders, Basic Weighted Average Units (Denominator) [Abstract] Weighted Average Number of Shares Outstanding, Diluted [Abstract] Weighted Average Number of Shares Outstanding, Basic Weighted Average Number of Shares Outstanding, Basic Dilutive units for long-term compensation plans Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Weighted Average Number of Shares Outstanding, Diluted Weighted Average Number of Shares Outstanding, Diluted Earnings Per Unit, Basic [Abstract] Earnings Per Share, Basic [Abstract] Income per common share - basic Earnings Per Share, Basic Earnings Per Unit, Diluted [Abstract] Earnings Per Share, Diluted [Abstract] Income per common share - diluted Earnings Per Share, Diluted Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Stock Option Exercises [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Award Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Stock Option [Member] Employee Stock Option [Member] Common shares [Member] Common Class A [Member] Stock Option Exercises [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Amount of Options Exercises in Period Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Document and Entity Information [Abstract] Document And Entity Information. Entities [Table] Entities [Table] Entity Information [Line Items] Entity Information [Line Items] Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key 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 Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Schedule of Antidilutive Options Excluded from Computation of Earnings Per Share [Table] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Antidilutive Securities [Axis] Antidilutive Securities [Axis] Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Stock Option [Member] Equity Option [Member] Antidilutive Options Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Options Excluded from Computation of Earnings Per Share Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Segment Reporting, Measurement Disclosures [Abstract] Schedule of Segment Reporting Information, by Segment, Revenue and Net Operating Income [Table Text Block] Schedule of Segment Reporting Information, by Segment [Table Text Block] Real Estate Properties Sold [Table Text Block] Real Estate Properties Sold [Table Text Block] This schedule details the real estate properties sold. This schedule includes the number of properties sold, amount of square feet sold and the amount of proceeds received by segment. Assets by Segment and Reconciliation to Consolidated[Table Text Block] Reconciliation of Assets from Segment to Consolidated [Table Text Block] Stockholders' Equity Attributable to Noncontrolling Interest [Abstract] Redeemable Noncontrolling Interest, by Legal Entity [Table] Redeemable Noncontrolling Interest, by Legal Entity [Table] Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Redeemable Noncontrolling Interest [Line Items] Redeemable Noncontrolling Interest [Line Items] Limited Partners' common units outstanding Limited Partners' Capital Account, Units Outstanding Market value of common units based on closing price Redeemable Noncontrolling Interest, Equity, Common, Fair Value Commitments and Contingencies Disclosure [Abstract] Supply Commitment [Table] Supply Commitment [Table] Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] Equity Method Investments [Member] Equity Method Investments [Member] Supply Commitment [Axis] Supply Commitment [Axis] Supply Commitment Arrangement [Domain] Supply Commitment Arrangement [Domain] Construction in Progress [Member] Construction in Progress [Member] Buildings and land parcels [Member] Land, Buildings and Improvements [Member] Tenant Improvements [Member] Leasehold Improvements [Member] Investment, Name [Axis] Investment, Name [Axis] Investment, Name [Domain] Investment, Name [Domain] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Supply Commitment [Line Items] Supply Commitment [Line Items] Net Rentable Area Net Rentable Area Number of Real Estate Properties Number of Real Estate Properties Total anticipated development cost Anticipated Aggregate Investment Total anticipated cost of investment in assets including but not limited to assets under construction. Development in Process Development in Process Deferred leasing costs in development Deferred Costs, Leasing, Gross Remaining amount committed or obligated to pay for the benefit of current or future tenants Supply Commitment, Remaining Minimum Amount Committed Tenant improvements not yet completed Supply Commitment, Remaining Maximum Amount Committed Supply Commitment, Remaining Maximum Amount Committed Earnings Per Share, Basic and Diluted [Line Items] Net income available to common shareholders Weighted Average Shares (Denominator) [Abstract] Dilutive shares for long-term compensation plans Weighted Average Number of Shares Outstanding, Diluted Debt Instrument, Fair Value Disclosure [Abstract] Fair Value, by Balance Sheet Grouping [Table Text Block] Derivative Instruments and Hedging Activities Disclosure [Abstract] Interest rate swaps [Text Block] Derivative Instruments and Hedging Activities Disclosure [Text Block] Noncontrolling Interests Noncontrolling Interest Disclosure [Text Block] Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract] Accumulated Other Comprehensive Income (Loss) Note [Text Block] Comprehensive Income (Loss) Note [Text Block] Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Accumulated Foreign Currency Adjustment Including Portion Attributable to Noncontrolling Interest [Member] Accumulated Foreign Currency Adjustment Including Portion Attributable to Noncontrolling Interest [Member] Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest [Member] Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest [Member] AOCI Including Portion Attributable to Noncontrolling Interest [Member] AOCI Including Portion Attributable to Noncontrolling Interest [Member] AOCI Attributable to Noncontrolling Interest [Member] AOCI Attributable to Noncontrolling Interest [Member] AOCI Attributable to Parent [Member] AOCI Attributable to Parent [Member] Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward] AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward] Beginning Balance Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Unrealized loss Other Comprehensive Income (Loss), before Reclassifications, Net of Tax Reclassification adjustment Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax Ending Balance Total accumulated other comprehensive loss Total accumulated other comprehensive loss included in shareholders' equity/owners' equity Stockholders' Equity Attributable to Parent Equity [Abstract] Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Common shares [Member] Share Repurchase Program [Axis] Share Repurchase Program [Axis] Share Repurchase Program [Domain] Share Repurchase Program [Domain] 2015 Share Repurchase Program [Member] 2015 Share Repurchase Program [Member] Share repurchase program authorized by the Board of Trustees in 2015. Class of Stock [Line Items] Class of Stock [Line Items] Authorized amount of shares available to be repurchased under a share repurchase plan Stock Repurchase Program, Authorized Amount Number of units repurchased during period Stock Repurchased During Period, Shares Amount paid for repurchase of units Stock Repurchased During Period, Value Treasury Stock Acquired, Average Cost Per Share Treasury Stock Acquired, Average Cost Per Share Derivative Instruments, Gain (Loss) [Table Text Block] Derivative Instruments, Gain (Loss) [Table Text Block] Authorized amount of shares available to be repurchased under a share repurchase plan Number of shares repurchased during period Amount paid for repurchase of shares Equity Method Investments and Joint Ventures [Abstract] Equity Method Investments and Joint Ventures Disclosure [Text Block] Equity Method Investments and Joint Ventures Disclosure [Text Block] Temporary Equity Disclosure [Abstract] Temporary Equity, by Class of Stock [Table] Temporary Equity, by Class of Stock [Table] Temporary Equity [Line Items] Temporary Equity [Line Items] Schedule of Temporary Equity [Table Text Block] Temporary Equity [Table Text Block] New Accounting Pronouncements, Policy [Policy Text Block] New Accounting Pronouncements, Policy [Policy Text Block] Earnings Per Share [Text Block] Earnings Per Share [Text Block] Long-term Purchase Commitment [Table] Long-term Purchase Commitment [Table] Category of Item Purchased [Axis] Category of Item Purchased [Axis] Long-term Purchase Commitment, Category of Item Purchased [Domain] Long-term Purchase Commitment, Category of Item Purchased [Domain] Land Purchases [Member] Capital Addition Purchase Commitments [Member] Long-term Purchase Commitment [Line Items] Long-term Purchase Commitment [Line Items] Remaining amount commitment to future land purchases Purchase Commitment, Remaining Minimum Amount Committed Supplemental Cash Flow Information [Abstract] Supplemental Disclosure to Statements of Cash Flows Cash Flow, Supplemental Disclosures [Text Block] Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract] Asset Impairment Charges [Text Block] Asset Impairment Charges [Text Block] Disclosure of Fair Value of Financial Instruments Fair Value Disclosures [Text Block] Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Measurement Basis [Axis] Measurement Basis [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement [Member] Portion at Fair Value Measurement [Member] Estimate of Fair Value Measurement [Member] Estimate of Fair Value Measurement [Member] Portion at Other than Fair Value Measurement [Member] Portion at Other than Fair Value Measurement [Member] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Fair Value, Inputs, Level 3 [Member] Fair Value, Inputs, Level 3 [Member] Fair Value by Liability Class [Axis] Liability Class [Axis] Fair Value, Liabilities, Measured on Recurring Basis, Unobservable Input Reconciliation, by Liability Class [Domain] Fair Value by Liability Class [Domain] Mortgage Loans Mortgages [Member] Unsecured Notes Unsecured Debt [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Long-term Debt, Fair Value Long-term Debt, Fair Value Schedule of Variable Interest Entities [Table] Schedule of Variable Interest Entities [Table] Liberty Comcast 1701 JFK Boulevard, LP [Member] Liberty Comcast 1701 JFK Boulevard, LP [Member] Liberty Comcast 1701 JFK Boulevard, LP formerly known as Liberty Commerz 1701 JFK Boulevard, LP [Member] Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] Philadelphia [Member] Philadelphia [Member] Philadelphia [Member] Variable Interest Entities [Axis] Variable Interest Entities [Axis] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Not Primary Beneficiary [Member] Variable Interest Entity, Not Primary Beneficiary [Member] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Other Investments [Member] Other Investments [Member] Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Equity investment in joint venture Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net Ownership interest in operating partnership - Limited Partnership Noncontrolling Interest, Ownership Percentage by Parent Equity Method Investment, Ownership Percentage Equity Method Investment, Ownership Percentage Maximum exposure to loss Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount Income Statement [Abstract] Statement [Table] Statement [Table] Statement [Line Items] Statement [Line Items] OPERATING REVENUE Revenues [Abstract] Rental Operating Leases, Income Statement, Lease Revenue Operating expense reimbursement Tenant Reimbursements Total operating revenue Revenues OPERATING EXPENSE Operating Expenses [Abstract] Rental property Direct Costs of Leased and Rented Property or Equipment Real estate taxes Real Estate Tax Expense General and administrative General and Administrative Expense Depreciation and amortization Depreciation, Depletion and Amortization, Nonproduction Impairment - real estate assets Impairment of Real Estate Total operating expenses Costs and Expenses Operating income Operating Income (Loss) OTHER INCOME (EXPENSE) Nonoperating Income (Expense) [Abstract] Interest and other income Other Income Interest expense Interest Expense Total other income (expense) Nonoperating Income (Expense) Income before gain on property dispositions, income taxes and equity in earnings of unconsolidated joint ventures Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest Gain on property dispositions Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property Income taxes Income Tax Expense (Benefit) Equity in earnings of unconsolidated joint ventures Income (Loss) from Equity Method Investments Income from continuing operations Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Noncontrolling interest – operating partnership Noncontrolling Interest in Net Income (Loss) Operating Partnerships, Redeemable Noncontrolling interest - consolidated joint ventures Noncontrolling Interest in Net Income (Loss) Joint Venture Partners, Nonredeemable Preferred unit distributions Comprehensive income attributable to common shareholders Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Other comprehensive loss - foreign currency translation Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax Other comprehensive loss - derivative instruments Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax Other comprehensive loss Other Comprehensive Income (Loss), Net of Tax Total comprehensive income Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Less: comprehensive income attributable to noncontrolling interest Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Comprehensive income attributable to common shareholders Comprehensive Income (Loss), Net of Tax, Attributable to Parent Earnings per common share Basic: Diluted: Distributions per common share or unit Common Stock, Dividends, Per Share, Declared Weighted average number of common shares outstanding Weighted Average Number of Shares Outstanding Reconciliation [Abstract] Basic Diluted Net income allocated to general partners Net Income (Loss) Allocated to General Partners Net income allocated to limited partners Net Income (Loss) Allocated to Limited Partners Amounts attributable to common shareholders Income Amounts Attributable to Parent, Disclosures [Abstract] Income from continuing operations Assets by Segment [Abstract] Assets by Segment [Abstract] Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] North America [Member] North America [Member] UNITED KINGDOM UNITED KINGDOM Operating Segments [Member] Operating Segments [Member] Corporate, Non-Segment [Member] Corporate, Non-Segment [Member] Carolinas Richmond [Member] Carolinas Richmond [Member] Carolinas Richmond [Member] Chicago Milwaukee [Member] Chicago Milwaukee [Member] Chicago Milwaukee Reportable Segment Florida [Member] Florida [Member] Area in the state of Florida which formally included the segments Tampa, Orlando and South Florida. Houston [Member] Houston [Member] Houston Reportable Segment Lehigh Central PA [Member] Lehigh Central PA [Member] Lehigh Central PA [Member] Minnesota [Member] Minnesota [Member] Minnesota Reportable Segment Southeastern PA [Member] Southeastern PA [Member] Southeastern PA United Kingdom [Member] United Kingdom [Member] United Kingdom Member. Other Segments [Member] Other Segments [Member] Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Assets Assets Statement of Stockholders' Equity [Abstract] Statement, Equity Components [Axis] General Partners Equity [Member] General Partner [Member] Limited Partners' Equity - Common Units [Member] Limited Partner [Member] Common Shares Of Beneficial Interest [Member] Common Stock [Member] Additional Paid-In Capital [Member] Additional Paid-in Capital [Member] Accumulated Other Comprehensive Income [Member] Distributions in Excess of Net Income [Member] Accumulated Distributions in Excess of Net Income [Member] Total Liberty Property Trust Shareholders' Equity [Member] Parent [Member] Noncontrolling interest operating partnership Common [Member] Noncontrolling interest operating partnership Common [Member] Noncontrolling Interest Operating Partnership. Noncontrolling interest-consolidated joint ventures [Member] Noncontrolling interest-consolidated joint ventures [Member] Noncontrolling Interest Consolidated Joint Ventures. Total Equity [Member] Stockholders' Equity, Total [Member] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Net proceeds from the issuance of common shares Stock Issued During Period, Value, New Issues Net income Contributions from partners Partners' Capital Account, Contributions Distributions Dividends, Common Stock Distributions to partners Partners' Capital Account, Distributions Share/Unit repurchase Share-based compensation Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Other comprehensive loss - foreign currency translation Other comprehensive loss - derivative instruments Increase (Decrease) in Temporary Equity [Roll Forward] Increase (Decrease) in Temporary Equity [Roll Forward] Noncontrolling Interest - Operating Partnership (Mezzanine) - Beginning Balance Temporary Equity, Carrying Amount, Including Portion Attributable to Noncontrolling Interests Net income (Mezzanine) Temporary Equity, Net Income Distributions (Mezzanine) Temporary Equity, Other Changes Noncontrolling Interest - Operating Partnership (Mezzanine) - Ending Balance Statement of Financial Position [Abstract] ASSETS Assets [Abstract] Real Estate [Abstract] Real Estate [Abstract] Land and land improvements Land and Land Improvements Building and improvements Investment Building and Building Improvements Less accumulated depreciation Real Estate Investment Property, Accumulated Depreciation Operating real estate Real Estate Investments, Other Development in progress Land held for development Land Available for Development Net real estate Real Estate Investment Property, Net Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Restricted cash Restricted Cash and Cash Equivalents Accounts receivable Accounts Receivable, Net Deferred rent receivable Deferred Rent Receivables, Net Deferred financing and leasing costs, net of accumulated amortization (March 31, 2016, $170,558; December 31, 2015, $175,243) Deferred Costs, Leasing, Net Investments in and advances to unconsolidated joint ventures Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures Assets held for sale Disposal Group, Including Discontinued Operation, Assets Prepaid expenses and other assets Prepaid Expense and Other Assets Total assets LIABILITIES Liabilities [Abstract] Mortgage loans Secured Debt Unsecured notes Unsecured Debt Credit facility Long-term Line of Credit Accounts payable Accounts Payable Accrued interest Interest Payable Dividend and distributions payable Dividends Payable Other liabilities Other Liabilities Total liabilities Liabilities Noncontrolling interest - operating partnership - 301,483 preferred units outstanding as of March 31, 2016 and December 31, 2015 EQUITY Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Common shares of beneficial interest, $.001 par value, 283,987,000 shares authorized; 146,603,946 and 147,577,984 shares issued and outstanding as of March 31, 2016 and December 31, 2015, respectively Common Stock, Value, Issued General partner’s equity - 146,603,946 and 147,577,984 common units outstanding as of March 31, 2016 and December 31, 2015, respectively General Partners' Capital Account Limited partners' equity Limited Partners' Capital Account Additional paid-in capital Additional Paid in Capital Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Distributions in excess of net income Accumulated Distributions in Excess of Net Income Total Liberty Property Trust shareholders' equity Noncontrolling interest - operating partnership Noncontrolling interest - operating partnerships Noncontrolling Interest in Operating Partnerships Noncontrolling interest - consolidated joint ventures Noncontrolling Interest in Joint Ventures Total owners' equity Total liabilities, noncontrolling interest - operating partnership and equity Liabilities and Equity Legal Matters [Abstract] Loss Contingency, Quantities [Abstract] Loss Contingency, Pending Claims, Number Loss Contingency, Pending Claims, Number Other [Abstract] Other Liabilities, Unclassified [Abstract] Letter of credit obligations Letters of Credit Outstanding, Amount Contractual Obligation Contractual Obligation Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Series I 2 [Member] Redeemable Preferred Stock [Member] Deferred financing and leasing costs, accumulated amortization Deferred Costs, Leasing, Accumulated Amortization Noncontrolling interest - operating partnership, preferred units outstanding Temporary Equity, Shares Outstanding Common shares of beneficial interest, par value per share Common Stock, Par or Stated Value Per Share Common shares of beneficial interest, shares authorized Common Stock, Shares Authorized Common shares of beneficial interest, shares issued Common Stock, Shares, Issued Common shares of beneficial interest, shares outstanding Common Stock, Shares, Outstanding Property, Plant and Equipment [Abstract] Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Limited Partners' Equity of the Operating Partnership [Abstract] Limited Partners' Equity of the Operating Partnership [Abstract] Schedule of Preferred Units [Table] Preferred Units [Line Items] Noncontrolling Interest Disclosure [Text Block] Schedule of Equity Method Investments [Table] Schedule of Equity Method Investments [Table] General Partner [Member] Related Party Transaction [Axis] Related Party Transaction [Axis] Related Party Transaction [Domain] Related Party Transaction [Domain] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Gain on equity method investments [Member] Gain (Loss) on Investments [Member] Liberty Washington, LP [Member] Liberty Washington, LP [Member] Liberty Washington, LP [Member] Disposal Group Classification [Axis] Disposal Group Classification [Axis] Disposal Group Classification [Domain] Disposal Group Classification [Domain] Disposal Group, Not Discontinued Operations [Member] Disposal Group, Not Discontinued Operations [Member] Extinguishment of Debt [Axis] Extinguishment of Debt [Axis] Extinguishment of Debt, Type [Domain] Extinguishment of Debt, Type [Domain] Mortgages [Member] Disposal Group Name [Axis] Disposal Group Name [Axis] Disposal Group Name [Domain] Disposal Group Name [Domain] Joint venture, 2016 sales [Member] Joint venture, 2016 sales [Member] Properties that were disposed of in the Company's equity method investments as a sale of property. Joint venture, 2016 deed in lieu transfer [Member] Joint venture, 2016 deed in lieu transfer [Member] Properties that are disposed of during 2016 in the Company's equity method investments by means of a deed in lieu transfer with the mortgage lender. Northern Virginia [Member] Northern Virginia [Member] Northern Virginia business segment [Member] Building and Building Improvements [Member] Building and Building Improvements [Member] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Schedule of Equity Method Investments [Line Items] Schedule of Equity Method Investments [Line Items] Liberty Washington LP [Abstract] Liberty Washington LP [Abstract] Liberty Washington LP [Abstract] Proceeds from Sale of Property Proceeds from Sale of Property, Plant, and Equipment Extinguishment of Debt, Amount Extinguishment of Debt, Amount Gain on extinguishment of debt Gains (Losses) on Extinguishment of Debt Gain on sale of properties Gain (Loss) on Sale of Properties Mortgage value in default Debt Instrument, Debt Default, Amount Business Combination, Separately Recognized Transactions [Axis] Business Combination, Separately Recognized Transactions [Axis] Business Combination, Separately Recognized Transactions [Domain] Business Combination, Separately Recognized Transactions [Domain] 2016 acquisitions [Member] 2016 acquisitions [Member] Property acquisitions during the year ended December 31, 2016. 2016 sales [Member] 2016 sales [Member] All real estate sales sold during the year ended December 31, 2016 Disposal Group, Held-for-sale, Not Discontinued Operations [Member] Disposal Group, Held-for-sale, Not Discontinued Operations [Member] Dallas [Member] Dallas [Member] Dallas [Member] Land and Land Improvements [Member] Land and Land Improvements [Member] Area of Land Area of Land Payments to Acquire Commercial Real Estate Proceeds from Sale of Real Estate Held-for-investment Proceeds from Sale of Real Estate Held-for-investment Segment Information Segment Reporting Disclosure [Text Block] 2016 Operating Leases, Future Minimum Payments, Remainder of Fiscal Year 2017 Operating Leases, Future Minimum Payments, Due in Two Years 2018 Operating Leases, Future Minimum Payments, Due in Three Years 2019 Operating Leases, Future Minimum Payments, Due in Four Years 2020 Operating Leases, Future Minimum Payments, Due in Five Years 2021 and thereafter Operating Leases, Future Minimum Payments, Due Thereafter Total Operating Leases, Future Minimum Payments Due Other Expenses [Abstract] Other Expenses [Abstract] Operating ground lease expense Operating Ground Lease Expense Operating Ground Lease Expense Schedule of Limited Partners' Capital Account by Class [Table] Schedule of Limited Partners' Capital Account by Class [Table] Limited Partners' Capital Account [Line Items] Limited Partners' Capital Account [Line Items] market value of the outstanding common units market value of the outstanding common units Market value of the limited partners' outstanding common units as of period end based on the closing price of the common shares of the trust. Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Statement of Cash Flows [Abstract] OPERATING ACTIVITIES Net Cash Provided by (Used in) Operating Activities [Abstract] Net income 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 and amortization Depreciation, Depletion and Amortization Amortization of deferred financing costs Amortization of Financing Costs Equity in earnings of unconsolidated joint ventures Distributions from unconsolidated joint ventures Proceeds from Equity Method Investment, Dividends or Distributions Gain on property dispositions Share-based compensation/Non-cash compensation Share-based Compensation Other Other Operating Activities, Cash Flow Statement Changes in operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Restricted cash Increase (Decrease) in Restricted Cash for Operating Activities Accounts receivable Increase (Decrease) in Accounts Receivable Deferred rent receivable Straight Line Rent Prepaid expenses and other assets Increase (Decrease) in Prepaid Expense and Other Assets Accounts payable Increase (Decrease) in Accounts Payable Accrued interest Increase (Decrease) in Interest Payable, Net Other liabilities Increase (Decrease) in Other Operating Liabilities 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] Investment in properties - acquisitions Payments to Acquire Buildings Investment in properties - other Payments for Capital Improvements Investments in and advances to unconsolidated joint ventures Payments to Acquire Equity Method Investments Distributions from unconsolidated joint ventures Proceeds from Equity Method Investment, Dividends or Distributions, Return of Capital Net proceeds from disposition of properties/land Investment in development in progress Payments to Develop Real Estate Assets Investment in land held for development Payments To Acquire And Develop Land The cash outflow associated with the purchase of or development of land held for investment. Payment of deferred leasing costs Payments for Leasing Costs Investing - Other Payments for (Proceeds from) Other Investing Activities 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] Net proceeds from issuance of common shares Proceeds from Issuance of Common Stock Share repurchase Payments for Repurchase of Common Stock Proceeds from unsecured notes Proceeds from Issuance of Unsecured Debt Repayment of unsecured notes Repayments of Unsecured Debt Repayments of mortgage loans Repayments of Secured Debt Proceeds from credit facility Proceeds from Long-term Lines of Credit Repayments on credit facility Repayments of Long-term Lines of Credit Payment of deferred financing costs Payments of Financing Costs Distribution paid on common shares Payments of Ordinary Dividends, Common Stock Distribution paid on units Payments of Ordinary Dividends, Noncontrolling Interest Capital contributions Proceeds from Contributed Capital Distributions to partners Payments of Capital Distribution Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities Net increase (decrease) in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect Decrease in cash and cash equivalents related to foreign currency translation Effect of Exchange Rate on Cash and Cash Equivalents Cash and cash equivalents at beginning of period Cash and cash equivalents at end of period Stockholders' Equity Note Disclosure [Text Block] Future Minimum Rental Payments Operating Leases of Lessee Disclosure [Table Text Block] Write-off of fully depreciated/amortized property and deferred costs Write off of fully depreciated property and deferred costs Write off of fully depreciated property and deferred costs Write-off of depreciated/amortized property and deferred costs due to sale Write Off Of Depreciated Property And Deferred Costs Due To Sale Write Off Of Depreciated Property And Deferred Costs Due To Sale Unrealized loss on cash flow hedge Unrealized gain (loss) on cash flow hedge, non cash transaction Unrealized gain (loss) on cash flow hedge, non cash transaction Changes in accrued development capital expenditures Construction in Progress Expenditures Incurred but Not yet Paid Segment Reporting [Abstract] Intersegment Eliminations [Member] Intersegment Eliminations [Member] Operating revenue Net operating income Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Abstract] Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table] Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table] Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items] Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items] Depreciation and amortization expense Impairment - real estate assets Gain on property dispositions General and administrative expense Other Other Nonoperating Income (Expense) Net income Derivative Instruments, Gain (Loss) [Table] Derivative Instruments, Gain (Loss) [Table] Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Contract [Domain] Derivative Contract [Domain] Interest Rate Swap [Member] Interest Rate Swap [Member] Interest Expense [Member] Interest Expense [Member] Other Comprehensive Income Location [Axis] Other Comprehensive Income Location [Axis] Other Comprehensive Income Location [Domain] Other Comprehensive Income Location [Domain] Other Comprehensive Income (Loss) [Member] Other Comprehensive Income (Loss) [Member] Hedging Designation [Axis] Hedging Designation [Axis] Hedging Designation [Domain] Hedging Designation [Domain] Designated as Hedging Instrument [Member] Designated as Hedging Instrument [Member] Hedging Relationship [Axis] Hedging Relationship [Axis] Hedging Relationship [Domain] Hedging Relationship [Domain] Cash Flow Hedging [Member] Cash Flow Hedging [Member] Derivative Instruments, Gain (Loss) [Line Items] Derivative Instruments, Gain (Loss) [Line Items] Amount of loss related to the effective portion recognized in other comprehensive loss Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net Amount of loss related to the effective portion subsequently reclassified to interest expense Derivative Instruments, Loss Reclassified from Accumulated OCI into Income, Effective Portion Amount of loss related to the ineffective portion recognized in interest expense Gain (Loss) on Interest Rate Cash Flow Hedge Ineffectiveness Summary of Derivative Instruments [Abstract] Summary of Derivative Instruments [Abstract] Interest Rate Derivatives [Abstract] Interest Rate Derivatives [Abstract] Number of interest rate swap contracts Number of Interest Rate Derivatives Held aggregate notional amount Derivative, Notional Amount Termination value of interest rate swap, including accrued interest Assets Needed for Immediate Settlement, Aggregate Fair Value Interest Rate Cash Flow Hedges [Abstract] Interest Rate Cash Flow Hedges [Abstract] Fair value of interest rate swaps Interest Rate Cash Flow Hedge Liability at Fair Value Amount estimated to be reclassified from accumulated other comprehensive income as an increase to interest expense Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net Units Liquidation Preference Temporary Equity, Redemption Price Per Share Dividend Rate Preferred Stock, Dividend Rate, Percentage Supplemental Disclosure to Statements of Cash Flows Schedule of Cash Flow, Supplemental Disclosures [Table Text Block] Discontinued Operations and Disposal Groups [Abstract]