Equity (Details) (USD $)	1 Months Ended	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2013
Equity [Line Items]
Common shares issued during period	23,000,000
Proceeds from issuance of common shares		$ 4,433,000	$ 297,823,000
Proceeds from Issuance of Common Stock, Gross	258,336,000
Proceeds from Issuance of Common Stock, Net of Issuance Costs	293,855,000
OP Unit Equivalent in Common Shares		1.13
Partners Capital Account, Shares Issued For Units Redeemed		2,605	88,442
OP Units Outstanding		3,445,000
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		4,439,000
Gains and Losses on Cash Flow Hedges, Ending		3,927,000
Transfers from noncontrolling interests:
Net income (loss) attributable to Lexington Realty Trust shareholders		886,000	(2,620,000)
Increase in additional paid-in-capital for redemption of noncontrolling OP units		(993,000)
Change from net income (loss) attributable to shareholders and transfers from noncontrolling interest		(107,000)	(2,162,000)
Parent [Member]
Equity [Line Items]
Partners' Capital Account, Redemption For Common Shares		(13,000)
Transfers from noncontrolling interests:
Increase in additional paid-in-capital for redemption of noncontrolling OP units			458,000
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		4,439,000
Other comprehensive loss before reclassifications		(1,784,000)
Amounts of loss reclassified from accumulated other comprehensive income to interest expense		1,272,000
Gains and Losses on Cash Flow Hedges, Ending		3,927,000
Accumulated Distributions in Excess of Net Income [Member]
Transfers from noncontrolling interests:
Net income (loss) attributable to Lexington Realty Trust shareholders		886,000	(2,620,000)
Direct Share Purchase Plan [Member]
Equity [Line Items]
Common shares issued during period		564,501	316,759
Proceeds from issuance of common shares		5,416,000	3,212,000
At The Market [Member]
Equity [Line Items]
Common shares issued 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
Officers [Member]
Equity [Line Items]
Deferred compensation arrangement with individual, shares issued			1,325,000
Deferred compensation arrangement with individual, fair value of shares issued			14,098,000
Trustees [Member]
Equity [Line Items]
Deferred compensation arrangement with individual, shares issued		14,000	37,500
Deferred compensation arrangement with individual, fair value of shares issued		142,000	399,000
Former LCIF II Partners [Member]
Equity [Line Items]
Partners Capital Account Units Exchanged For Cash		170,193
Cash Acquired from Acquisition		$ 1,962,000