Investment in and Advances to Non-Consolidated Entities	12 Months Ended
Investment in and Advances to Non-Consolidated Entities	Dec. 31, 2017
Investments in and Advances to Affiliates [Line Items]
Investment in and Advances to Non-Consolidated Entities	Investment in and Advances to Non-Consolidated Entities As of December 31, 2017, the Company had ownership interests ranging from 15% to 25% in certain non-consolidated entities, which primarily own single-tenant net-leased assets. The acquisitions of these assets by the non-consolidated entities were partially funded through non-recourse mortgage debt with an aggregate balance of $96,603 at December 31, 2017 (the Company's proportionate share was $20,886). In addition, in 2017, the Company formed a non-consolidated joint venture with a developer to pursue industrial build-to-suit opportunities. The Company's initial contribution of $5,831 was used to acquire a 151-acre parcel of developable land. In February 2017, the Company sold its 40% tenant-in-common interest in its Oklahoma City, Oklahoma office property for $6,198. In January 2016, the Company received $6,681 in connection with the sale of a non-consolidated office property in Russellville, Arkansas. The Company recognized gains of $1,452 and $5,378, respectively, in connection with these sales, which are included in equity in earnings of non-consolidated entities. During 2017, the Company recognized an impairment charge of $3,512 on its investment in a retail property in Palm Beach Gardens, Florida due to the bankruptcy of its tenant. This impairment charge reduced the Company's investment balance to zero. In November 2014, the Company formed a joint venture to construct a private school in Houston, Texas. As of December 31, 2017, the Company had a 25% equity interest in the joint venture. The joint venture completed the project during 2016 for a total construction cost of $79,964. The Company was contractually obligated to provide construction financing to the joint venture up to $56,686. During 2017, the Company received $49,085 in full satisfaction of the construction financing from the proceeds of a $50,000 third-party financing. LRA earns advisory fees from certain of these non-consolidated entities for services related to acquisitions, asset management and debt placement. Advisory fees earned from these non-consolidated investments were $807, $693 and $223 for the years ended December 31, 2017, 2016 and 2015.
LCIF [Member]
Investments in and Advances to Affiliates [Line Items]
Investment in and Advances to Non-Consolidated Entities	Investments in and Advances to Non-Consolidated Entities In July 2014, the Partnership acquired a 1.0% interest in an office property in Philadelphia, Pennsylvania for $263. The Partnership accounts for this investment under the cost basis of accounting. On September 1, 2012, the Partnership acquired a 2% equity interest in Net Lease Strategic Assets Fund L.P. (“NLS”) for cash of $189 and the issuance of 457,211 limited partner units to Lexington. The Partnership's carrying value in NLS at December 31, 2017 and 2016 was $6,175 and $5,224, respectively. The Partnership recognized net income from NLS of $458, $302 and $141 in equity in earnings from non-consolidated entities during 2017, 2016 and 2015, respectively. The Partnership contributed $1,737 and $81 to NLS in 2017 and 2016. In addition, the Partnership received distributions of $1,244, $781 and $636 from NLS in 2017, 2016 and 2015, respectively.