Commitments and Contingencies	12 Months Ended
Commitments and Contingencies	Dec. 31, 2017
Commitments and Contingencies [Line Items]
Commitments and Contingencies	Commitments and Contingencies In addition to the commitments and contingencies disclosed elsewhere, the Company has the following commitments and contingencies. The Company is obligated under certain tenant leases, including its proportionate share for leases for non-consolidated entities, to fund the expansion of the underlying leased properties. The Company, under certain circumstances, may guarantee to tenants the completion of base building improvements and the payment of tenant improvement allowances and lease commissions on behalf of its subsidiaries. The Company and LCIF are parties to a funding agreement under which the Company may be required to fund distributions made on account of LCIF's OP units. Pursuant to the funding agreement, the parties agreed that, if LCIF does not have sufficient cash available to make a quarterly distribution to its limited partners in an amount in accordance with the partnership agreement, Lexington will fund the shortfall. Payments under the agreement will be made in the form of loans to LCIF and will bear interest at prevailing rates as determined by the Company in its discretion but, no less than the applicable federal rate. LCIF's right to receive these loans will expire if no OP units remain outstanding and all such loans are repaid. No amounts have been advanced under this agreement. From time to time, the Company is directly or indirectly involved in legal proceedings arising in the ordinary course of business. Management believes, based on currently available information, and after consultation with legal counsel, that although the outcomes of those normal course proceedings are uncertain, the results of such proceedings, in the aggregate, will not have a material adverse effect on the Company's business, financial condition and results of operations. GSMSC II 2006-GG6 Bridgewater Hills Corporate Center, LLC v. Lexington Realty Trust (Supreme Court of the State of New York, County of New York-Index No. 653117/2015) On September 16, 2015, GSMSC II 2006-GG6 Bridgewater Hills Corporate Center, LLC commenced an action as lender against the Company based on a limited guaranty of recourse obligations executed by a predecessor entity of the Company in connection with a mortgage loan secured by a property owner subsidiary's commercial property in Bridgewater, New Jersey. The property owner subsidiary defaulted due to non-payment after the sole tenant vacated at the end of the lease term. The lender claimed approximately $9,200 in order to satisfy the outstanding amount of the loan, plus interest, reasonable attorney’s fees and other costs and disbursements related thereto. The lender claimed that the Company's limited guaranty was triggered due to the merger of Newkirk Realty Trust, Inc. and Lexington Corporate Properties Trust on December 31, 2006, arguing that it constituted an event of default because it was a transfer that was not permitted by the loan agreement. The limited guaranty provided that the guarantor's liability for the guaranteed obligations shall not exceed $10,000. The Company filed a motion to dismiss, which was generally denied. The parties conducted discovery consisting of document production. A mediation was held on October 5, 2017. As a result of discussions, following the mediation, a settlement agreement was executed and the Company made a $2,050 payment in full settlement of the lender's claims. The action was subsequently dismissed. The lender also brought a foreclosure action against the property owner subsidiary. A foreclosure sale was held September 13, 2016 and the lender acquired the property for a nominal amount. During 2017, the Company incurred $2,255 in legal costs relating to this litigation, which are included in general and administrative expense on the Company's consolidated statement of operations. Other. As of December 31, 2017, four of the Company's executive officers had employment contracts and were entitled to severance benefits upon termination by the Company without cause or termination by the executive officer with good reason, in each case, as defined in the employment contract. The employment agreements expired in January 2018. In January 2018, the Company adopted an executive severance policy and entered into related agreements with certain of its executive officers whereby the Company's executives are entitled to severance benefits upon substantially similar events. Also, in January 2018, the Company entered into retirement agreements with two of the four executive officers that had employment contracts. One of the retirement agreements provides for contingent payments, not to exceed $795, in future years upon the receipt of certain incentive fees by the Company, if any.
LCIF [Member]
Commitments and Contingencies [Line Items]
Commitments and Contingencies	Commitments and Contingencies In addition to the commitments and contingencies disclosed elsewhere, the Partnership has the following commitments and contingencies. The Partnership is obligated under certain tenant leases, including its proportionate share for leases for non-consolidated entities, to fund the expansion of the underlying leased properties. The Partnership, under certain circumstances, may guarantee to tenants the completion of base building improvements and the payment of tenant improvement allowances and lease commissions on behalf of its subsidiaries. The Partnership and Lexington are parties to a funding agreement under which Lexington may be required to fund distributions made on account of OP units. Pursuant to the funding agreement, the parties agreed that, if the Partnership does not have sufficient cash available to make a quarterly distribution to its limited partners in an amount in accordance with the partnership agreement, Lexington will fund the shortfall. Payments under the agreement will be made in the form of loans to the Partnership and will bear interest at prevailing rates as determined by Lexington in its discretion, but no less than the applicable federal rate. The Partnership's right to receive these loans will expire if no OP units remain outstanding and all such loans repaid. No amounts have been advanced under this agreement. From time to time, the Partnership is directly or indirectly involved in legal proceedings arising in the ordinary course of the Partnership's business. The Partnership believes, based on currently available information, and after consultation with legal counsel, that although the outcomes of those normal course proceedings are uncertain, the results of such proceedings, in the aggregate, will not have a material adverse effect on the Partnership's business, financial condition and results of operations. In May 2014, the Partnership guaranteed $250,000 aggregate principal amount of 4.40% Senior Notes due 2024 (“2024 Senior Notes”) issued by Lexington at an issuance price of 99.883% of the principal amount and in June 2013, the Partnership guaranteed $250,000 aggregate principal amount of 4.25% Senior Notes due 2023 (“2023 Senior Notes”) issued by Lexington at an issuance price of 99.026% of the principal amount, collectively the Senior Notes. The Senior Notes are unsecured, pay interest semi-annually in arrears and mature in June 2024 and 2023, respectively. Lexington may redeem the notes at its option at any time prior to maturity in whole or in part by paying the principal amount of the notes being redeemed plus a premium.