Equity (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended			9 Months Ended			9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010	Sep. 30, 2011 Public Offering And Direct Share Purchase Plan Proceeds [Member]	Sep. 30, 2010 Public Offering And Direct Share Purchase Plan Proceeds [Member]	Mar. 31, 2010 Six Percent Convertible Guaranteed Note [Member]	Sep. 30, 2011 Accumulated Distributions in Excess of Net Income [Member]	Sep. 30, 2010 Accumulated Distributions in Excess of Net Income [Member]
Equity [Line Items]
Common shares issued through public offering and direct share purchase plan during period			10,733,673	11,949,400
Proceeds from issuance of common shares			$ 90,505	$ 70,698		$ 96,595	$ 77,422
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt				13,134						0
Debt Instrument, Interest Rate, Stated Percentage								6.00%
Unrealized gain (loss) on interest rate swap in Accumulated Other Comprehensive Income	1,236		1,236		(106)
OP Unit Equivalent in Common Shares			1.13
OP Units Outstanding	4,078,000		4,078,000
Partners Capital Account, Shares Issued For Units Redeemed			340,550	352,456
Partners Capital Units With Liquidation Preference Number			0
Transfers from noncontrolling interests:
Net loss attributable to Lexington Realty Trust shareholders	(30,844)	7,340	(103,794)	(51,687)					(92,611)	(44,534)
Increase in additional paid-in-capital for redemption of noncontrolling OP units			1,876	1,897
Change from net loss attributable to shareholders and transfers from noncontrolling interest			$ (90,735)	$ (42,637)