Consolidated Statement of Equity (USD $) In Thousands	Total	Common Shares Of Beneficial Interest [Member]	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive Income [Member]	Distributions in Excess of Net Income [Member]	Common Shares Held in Treasury [Member]	Total Liberty Property Trust Shareholders' Equity [Member]	Noncontrolling interest operating partnership-Common [Member]	Noncontrolling interest operating partnership-Preferred [Member]	Noncontrolling interest-consolidated joint ventures [Member]	Liberty Property Limited Partnership [Member]	Liberty Property Limited Partnership [Member] General Partners Equity [Member]	Liberty Property Limited Partnership [Member] Noncontrolling interest operating partnership-Common [Member]	Liberty Property Limited Partnership [Member] Noncontrolling interest operating partnership-Preferred [Member]	Liberty Property Limited Partnership [Member] Noncontrolling interest-consolidated joint ventures [Member]	Common Units [Member] Additional Paid-In Capital [Member]	Common Units [Member] Total Liberty Property Trust Shareholders' Equity [Member]	Common Units [Member] Noncontrolling interest operating partnership-Common [Member]	preferred unit [Member]	preferred unit [Member] Noncontrolling interest operating partnership-Preferred [Member]
Beginning Balance at Dec. 31, 2011	$ 2,459,756	$ 117	$ 2,617,355	$ (429)	$ (461,498)	$ (51,951)	$ 2,103,594	$ 64,428	$ 287,959	$ 3,775	$ 2,459,756	$ 2,103,594	$ 64,428	$ 287,959	$ 3,775
Net proceeds from the issuance of common shares	31,234	2	31,232				31,234
Net income	77,282				71,200		71,200	2,292	3,790	0	77,282	71,200	2,292	3,790	0
Contributions from partners											37,671	37,671
Distributions to partners											(122,610)	(111,421)	(3,705)	(7,484)
Distributions	(122,610)				(111,421)		(111,421)	(3,705)	(7,484)
Noncash compensation	6,437		6,437				6,437
Foreign currency translation adjustment	801			775			775	26			801	775	26
Redemption of noncontrolling interests - common units											(224,689)			(224,689)		1,150	1,150	(1,150)	(224,689)	(224,689)
Redemption of limited partners common units for common shares												1,150	(1,150)
Preferred Stock Redemption Discount	3,689								3,689		3,689			3,689
Ending Balance at Jun. 30, 2012	2,231,900	119	2,656,174	346	(501,719)	(51,951)	2,102,969	61,891	63,265	3,775	2,231,900	2,102,969	61,891	63,265	3,775
Beginning Balance at Mar. 31, 2012
Net income	37,680										37,680
Foreign currency translation adjustment	(1,515)										(1,515)
Ending Balance at Jun. 30, 2012	$ 2,231,900					$ (51,951)					$ 2,231,900