Equity (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Equity [Line Items]
Common shares issued through public offering and direct share purchase plan during period									36,012,313	18,289,557	11,109,760
Proceeds from issuance of common shares									$ 434,927,000	$ 162,747,000	$ 99,730,000
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures									1,893,409	643,450	609,182
OP Unit Equivalent in Common Shares									1.13
OP Units Outstanding	3,618,000								3,618,000
Partners Capital Account, Shares Issued For Units Redeemed									202,241	257,427	398,927
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax [Roll Forward]
Gains and Losses on Cash Flow Hedges, Beginning				(6,224,000)					(6,224,000)
Other comprehensive income before reclassifications									7,559,000
Amounts of loss reclassified from accumulated other comprehensive loss to interest expense									3,104,000
Gains and Losses on Cash Flow Hedges, Ending	4,439,000				(6,224,000)				4,439,000	(6,224,000)
Transfers from noncontrolling interests:
Net income (loss) attributable to Lexington Realty Trust shareholders	(7,001,000)	5,155,000	7,832,000	(2,123,000)	(1,755,000)	175,289,000	5,626,000	5,478,000	3,863,000	184,638,000	(89,778,000)
Increase in additional paid-in-capital for redemption of noncontrolling OP units									1,053,000	1,343,000	2,187,000
Change from net income (loss) attributable to shareholders and transfers from noncontrolling interests									2,683,000	181,659,000	(77,397,000)
Accumulated Distributions in Excess of Net Income [Member]
Transfers from noncontrolling interests:
Net income (loss) attributable to Lexington Realty Trust shareholders									1,630,000	180,316,000	(79,584,000)
Series C [Member]
Equity [Line Items]
Preferred Stock, Dividend Rate, Per-Dollar-Amount									$ 3.25
Preferred Shares to Common Shares Conversion Ratio									2.4339
Series C [Member] | Minimum [Member]
Equity [Line Items]
Common Share Closing Price Percent of Conversion Price									125.00%
Cumulative Convertible [Member] | Series C [Member]
Equity [Line Items]
Preferred Stock, Shares Outstanding	1,935,400				1,935,400				1,935,400	1,935,400
Preferred Stock Aggregate Liquidation Preference Value	96,770,000				96,770,000				96,770,000	96,770,000
Public Offering And Direct Share Purchase Plan Proceeds [Member]
Equity [Line Items]
Proceeds from issuance of common shares									399,566,000	164,429,000	98,953,000
At The Market [Member]
Equity [Line Items]
Common shares issued through public offering and direct share purchase plan during period									3,409,927
Stockholders' Equity, Share Issuance Plan, Value Authorized									100,000,000
Stock Issued During Period, Value, New Issues									$ 36,884,000