Equity (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Equity [Line Items]
Common shares issued during period			23,000,000
Proceeds from Issuance of Common Stock, Gross			$ 258,336
Proceeds from Issuance of Common Stock, Net of Issuance Costs			293,934
Proceeds from issuance of common shares			302,987	4,291
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)
Gains and Losses on Cash Flow Hedges, Ending	3,912		3,912
OP Unit Equivalent in Common Shares			1.13
Partners Capital Account, Shares Issued For Units Redeemed			164,596	66,652
OP Units Outstanding	3,651,000		3,651,000
Transfers from noncontrolling interests:
Net income (loss) attributable to Lexington Realty Trust shareholders	6,732	4,510	4,112	8,121
Increase in additional paid-in-capital for redemption of noncontrolling OP units			861	353
Change from net income (loss) attributable to shareholders and transfers from noncontrolling interest			4,973	8,474
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
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)
Other comprehensive income before reclassifications			8,851
Amounts of loss reclassified from accumulated other comprehensive loss to interest expense			1,285
Gains and Losses on Cash Flow Hedges, Ending	3,912		3,912
Accumulated Distributions in Excess of Net Income [Member]
Transfers from noncontrolling interests:
Net income (loss) attributable to Lexington Realty Trust shareholders			4,112	8,121
Direct Share Purchase Plan [Member]
Equity [Line Items]
Common shares issued during period			690,873	563,639
Proceeds from issuance of common shares			7,466	4,291
At The Market [Member]
Equity [Line Items]
Common shares issued during period			3,409,927
Stock Issued During Period, Value, New Issues			36,884
Stockholders' Equity, Share Issuance Plan, Value Authorized			100,000
Officers [Member]
Transfers from noncontrolling interests:
Deferred compensation arrangement with individual, shares issued			1,325,000
Deferred compensation arrangement with individual, fair value of shares issued			14,098
Trustees [Member]
Transfers from noncontrolling interests:
Deferred compensation arrangement with individual, shares issued			37,500
Deferred compensation arrangement with individual, fair value of shares issued			$ 399