Consolidated Statement of Equity (USD $)	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]
Beginning 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	$ 3,035,844,000	$ 56,713,000	$ 0	$ 3,622,000
Net proceeds from the issuance of common shares	44,097,000	1,000	44,096,000				44,097,000
Net income	139,664,000				135,572,000		135,572,000	3,264,000	354,000	474,000	139,664,000	135,572,000	3,264,000	354,000	474,000
Redemption of limited partners common units for common shares											0	48,000	(48,000)
Contributions from partners											54,519,000	54,519,000
Distributions	(216,195,000)				(210,505,000)		(210,505,000)	(5,159,000)	(354,000)	(177,000)
Distributions to partners											(216,195,000)	(210,505,000)	(5,159,000)	(354,000)	(177,000)
Share-based compensation	10,422,000		10,422,000				10,422,000
Other comprehensive (loss) income - foreign currency translation	(5,189,000)			(5,068,000)			(5,068,000)	(121,000)			(5,189,000)	(5,068,000)	(121,000)
Other comprehensive income (loss) - change in net unrealized gain on derivative instruments	(990,000)			(967,000)			(967,000)	(23,000)			(990,000)	(967,000)	(23,000)
Redemption of noncontrolling interests - common units	0		48,000				48,000	(48,000)
Ending Balance at Sep. 30, 2014	3,067,988,000	149,000	3,724,184,000	3,707,000	(666,646,000)	(51,951,000)	3,009,443,000	54,626,000	0	3,919,000	3,067,988,000	3,009,443,000	54,626,000	0	3,919,000
Beginning Balance at Jun. 30, 2014
Net income	35,451,000										35,451,000
Other comprehensive (loss) income - foreign currency translation	(13,000,000)										(13,000,000)
Other comprehensive income (loss) - change in net unrealized gain on derivative instruments	666,000										666,000
Ending Balance at Sep. 30, 2014	$ 3,067,988,000					$ (51,951,000)					$ 3,067,988,000