Consolidated Statement of Equity (USD $)	Total USD ($)	Common Shares Of Beneficial Interest [Member] USD ($)	Additional Paid-In Capital [Member] USD ($)	Accumulated Other Comprehensive Income [Member] USD ($)	Distributions in Excess of Net Income [Member] USD ($)	Common Shares Held in Treasury [Member] USD ($)	Total Liberty Property Trust Shareholders' Equity [Member] USD ($)	Noncontrolling interest operating partnership-Common [Member] USD ($)	Noncontrolling interest operating partnership-Preferred [Member] USD ($)	Noncontrolling interest-consolidated joint ventures [Member] USD ($)	Stockholders' Equity, Total [Member] USD ($)	Liberty Property Limited Partnership [Member] USD ($)	Liberty Property Limited Partnership [Member] General Partners Equity [Member] USD ($)	Liberty Property Limited Partnership [Member] Noncontrolling interest operating partnership-Common [Member] USD ($)	Liberty Property Limited Partnership [Member] Noncontrolling interest operating partnership-Preferred [Member] USD ($)	Liberty Property Limited Partnership [Member] Noncontrolling interest-consolidated joint ventures [Member] USD ($)	Liberty Property Limited Partnership [Member] Stockholders' Equity, Total [Member] USD ($)	Common shares [Member]	Common Units [Member] Liberty Property Limited Partnership [Member] General Partner [Member]	Common Units [Member] Liberty Property Limited Partnership [Member] Limited Partner [Member]
Beginning Balance at Dec. 31, 2011		$ 117,000	$ 2,617,355,000	$ (429,000)	$ (461,498,000)	$ (51,951,000)	$ 2,103,594,000	$ 64,428,000	$ 287,959,000	$ 3,775,000	$ 2,459,756,000		$ 2,103,594,000	$ 64,428,000	$ 287,959,000	$ 3,775,000	$ 2,459,756,000
Noncontrolling interest - operating partnership (mezzanine) - Beginning of Period at Dec. 31, 2011	7,537,000											7,537,000
Common shares outstanding - Beginning Balance at Dec. 31, 2011																		117,352,353
General Partner's units outstanding - Beginning Balance at Dec. 31, 2011																			116,102,444
Limited Partners' units outstanding - Beginning Balance at Dec. 31, 2011																				3,808,746
Contributions from partners													68,767,000				68,767,000
Distributions to partners													(223,695,000)	(7,109,000)	(9,430,000)	(179,000)	(240,413,000)
Net proceeds from the issuance of common shares		2,000	58,708,000	0	0	0	58,710,000	0	0	0	58,710,000
Net income	147,751,000	0	0	0	137,436,000	0	137,436,000	4,378,000	5,740,000	(275,000)	147,279,000	147,751,000	137,436,000	4,378,000	5,740,000	(275,000)	147,279,000
Redemption of limited partners common units for common shares													1,581,000	(1,581,000)
Distributions		0	0	0	(223,695,000)	0	(223,695,000)	(7,109,000)	(9,430,000)	(179,000)	(240,413,000)
Noncash compensation		0	10,057,000	0	0	0	10,057,000	0	0	0	10,057,000
Foreign currency translation adjustment	3,436,000	0	0	3,329,000	0	0	3,329,000	107,000	0	0	3,436,000	3,436,000	3,329,000	107,000			3,436,000
Other comprehensive income - change in net unrealized (loss) gain on derivatives	0											0
Partners' Capital, Other												0	0	0	0		0
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests, Common Units		0	1,581,000	0	0	0	1,581,000	(1,581,000)	0	0	0
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests, Preferred Units		0	0	0	0	0	0	0	(224,694,000)	0	(224,694,000)
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests															(224,694,000)		(224,694,000)
Excess of preferred unit carrying amount over redemption	3,689,000	0	0	0	0	0	0	0	3,689,000	0	3,689,000	3,689,000			3,689,000		3,689,000
Number of common shares issued																		2,273,528
Number of common units issued																			2,273,528
Number of common units converted																		94,895	94,895	94,895
Temporary Equity, Net Income	472,000											472,000
Temporary Equity, Distributions	(472,000)											(472,000)
Ending Balance at Dec. 31, 2012		119,000	2,687,701,000	2,900,000	(547,757,000)	(51,951,000)	2,091,012,000	60,223,000	63,264,000	3,321,000	2,217,820,000		2,091,012,000	60,223,000	63,264,000	3,321,000	2,217,820,000
Noncontrolling interest - operating partnership (mezzanine) - End of Period at Dec. 31, 2012	7,537,000											7,537,000
Common shares outstanding - Ending Balance at Dec. 31, 2012																		119,720,776
General Partner's units outstanding - Ending Balance at Dec. 31, 2012																			118,470,867
Limited Partners' units outstanding - Ending Balance at Dec. 31, 2012																				3,713,851
Contributions from partners													979,444,000				979,444,000
Distributions to partners													(253,694,000)	(6,995,000)	(1,647,000)	(352,000)	(262,688,000)
Net proceeds from the issuance of common shares		29,000	969,439,000	0	0	0	969,468,000	0	0	0	969,468,000
Net income	219,594,000	0	0	0	209,738,000	0	209,738,000	5,848,000	2,883,000	653,000	219,122,000	219,594,000	209,738,000	5,848,000	2,883,000	653,000	219,122,000
Redemption of limited partners common units for common shares													2,502,000	(2,502,000)
Distributions		0	0	0	(253,694,000)	0	(253,694,000)	(6,995,000)	(1,647,000)	(352,000)	(262,688,000)
Noncash compensation		0	9,976,000	0	0	0	9,976,000	0	0	0	9,976,000
Foreign currency translation adjustment	5,397,000	0	0	5,296,000	0	0	5,296,000	101,000	0	0	5,397,000	5,397,000	5,296,000	101,000			5,397,000
Other comprehensive income - change in net unrealized gain on derivatives	1,584,000												1,546,000	38,000	0	0	1,584,000
Other comprehensive income - change in net unrealized (loss) gain on derivatives	1,584,000	0	0	1,546,000	0	0	1,546,000	38,000	0	0	1,584,000	1,584,000
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests, Common Units		0	2,502,000	0	0	0	2,502,000	(2,502,000)	0	0	0
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests, Preferred Units		0	0	0	0	0	0	0	(63,264,000)	0	(63,264,000)
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests															(63,264,000)		(63,264,000)
Excess of preferred unit carrying amount over redemption	(1,236,000)	0	0	0	0	0	0	0	(1,236,000)	0	(1,236,000)	(1,236,000)			(1,236,000)		(1,236,000)
Number of common shares issued																		27,968,740
Number of common units issued																			27,968,740
Number of common units converted																		157,285	157,285	157,285
Temporary Equity, Net Income	472,000											472,000
Temporary Equity, Distributions	(472,000)											(472,000)
Ending Balance at Dec. 31, 2013	3,096,179,000	148,000	3,669,618,000	9,742,000	(591,713,000)	(51,951,000)	3,035,844,000	56,713,000	0	3,622,000	3,096,179,000	3,096,179,000	3,035,844,000	56,713,000	0	3,622,000	3,096,179,000
Noncontrolling interest - operating partnership (mezzanine) - End of Period at Dec. 31, 2013	7,537,000											7,537,000
Common shares outstanding - Ending Balance at Dec. 31, 2013	147,846,801											146,596,892						147,846,801
General Partner's units outstanding - Ending Balance at Dec. 31, 2013																			146,596,892
Limited Partners' units outstanding - Ending Balance at Dec. 31, 2013												3,556,566								3,556,566
Contributions from partners													70,930,000				70,930,000
Distributions to partners													(281,066,000)	(6,731,000)	0	(250,000)	(288,047,000)
Net proceeds from the issuance of common shares		2,000	58,471,000	0	0	0	58,473,000	0	0	0	58,473,000
Net income	224,163,000	0	0	0	217,910,000	0	217,910,000	5,234,000	0	547,000	223,691,000	224,163,000	217,910,000	5,234,000	0	547,000	223,691,000
Redemption of limited partners common units for common shares													48,000	(48,000)			0
Distributions		0	0	0	(281,066,000)	0	(281,066,000)	(6,731,000)	0	(250,000)	(288,047,000)
Noncash compensation		0	12,457,000	0	0	0	12,457,000	0	0	0	12,457,000
Foreign currency translation adjustment	(14,415,000)	0	0	(14,079,000)	0	0	(14,079,000)	(336,000)	0	0	(14,415,000)	(14,415,000)	(14,079,000)	(336,000)			(14,415,000)
Other comprehensive income - change in net unrealized gain on derivatives	(3,419,000)	0											(1,915,000)	(46,000)	0	0	(1,961,000)
Other comprehensive income - change in net unrealized (loss) gain on derivatives	(1,961,000)		0	(1,915,000)	0	0	(1,915,000)	(46,000)	0	0	(1,961,000)	(1,961,000)
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests, Common Units		0	48,000	0	0	0	48,000	(48,000)	0	0	0
Excess of preferred unit carrying amount over redemption												0
Excess of preferred unit carrying amount over redemption												0
Number of common shares issued																		1,957,378
Number of common units issued																			1,957,378
Number of common units converted																		3,000	3,000	3,000
Temporary Equity, Net Income	472,000											472,000
Temporary Equity, Distributions	(472,000)											(472,000)
Ending Balance at Dec. 31, 2014	3,086,377,000	150,000	3,740,594,000	(6,252,000)	(654,869,000)	(51,951,000)	3,027,672,000	54,786,000	0	3,919,000	3,086,377,000	3,086,377,000	3,027,672,000	54,786,000	0	3,919,000	3,086,377,000
Noncontrolling interest - operating partnership (mezzanine) - End of Period at Dec. 31, 2014	$ 7,537,000											$ 7,537,000
Common shares outstanding - Ending Balance at Dec. 31, 2014	149,807,179											148,557,270						149,807,179
General Partner's units outstanding - Ending Balance at Dec. 31, 2014																			148,557,270
Limited Partners' units outstanding - Ending Balance at Dec. 31, 2014												3,553,566								3,553,566