Consolidated Statement of Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	AOCI Attributable to Parent [Member]	Accumulated Distributions in Excess of Net Income [Member]	Parent [Member]	Noncontrolling interest operating partnership Common [Member]	Noncontrolling interest-consolidated joint ventures [Member]	Liberty Property Limited Partnership [Member]	Liberty Property Limited Partnership [Member] General Partner [Member]	Liberty Property Limited Partnership [Member] Limited Partner [Member]	Liberty Property Limited Partnership [Member] Noncontrolling interest-consolidated joint ventures [Member]	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]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive loss - foreign currency translation activity	$ 16,314								$ 16,314
Other comprehensive income - derivative instruments activity	$ 366								$ 366
Common shares outstanding - Beginning Balance (shares) at Dec. 31, 2017	147,450,691								147,450,691				147,450,691
Beginning Balance at Dec. 31, 2017	$ 3,148,366	$ 147	$ 3,674,978	$ (37,797)	$ (549,970)	$ 3,087,358	$ 56,159	$ 4,849	$ 3,148,366	$ 3,087,358	$ 56,159	$ 4,849
General Partner's units outstanding - Beginning Balance (units) at Dec. 31, 2017														147,450,691
Limited Partners' units outstanding - Beginning Balance (units) at Dec. 31, 2017	3,520,205								3,520,205						3,520,205
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net proceeds from the issuance of common shares	$ 5,255	1	5,254			5,255
Net proceeds from issuance of common shares (shares)													361,630
Net income	318,332				309,938	309,938	7,384	1,010	$ 318,332	309,938	7,384	1,010
Contributions from partners									13,654	13,654
Contributions from partners (units)														361,630
Distributions	(182,040)				(177,325)	(177,325)	(4,283)	(432)
Distributions to partners									(182,040)	(177,325)	(4,283)	(432)
Share-based compensation	8,399		8,399			8,399
Other comprehensive loss - foreign currency translation activity	(9,221)			(9,007)		(9,007)	(214)		(9,221)	(9,007)	(214)
Other comprehensive income - derivative instruments activity	$ 493			482		482	11		$ 493	482	11
Common shares outstanding - Ending Balance (shares) at Sep. 30, 2018	147,812,321								147,812,321				147,812,321
General Partner's units outstanding - Ending Balance (units) at Sep. 30, 2018														147,812,321
Limited Partners' units outstanding - Ending Balance (units) at Sep. 30, 2018	3,520,205								3,520,205						3,520,205
Ending Balance at Sep. 30, 2018	$ 3,289,584	$ 148	$ 3,688,631	$ (46,322)	$ (417,357)	$ 3,225,100	$ 59,057	$ 5,427	$ 3,289,584	$ 3,225,100	$ 59,057	$ 5,427
Noncontrolling Interest - Operating Partnership (Mezzanine) - Beginning Balance at Dec. 31, 2017	7,537								7,537
Increase (Decrease) in Temporary Equity [Roll Forward]
Net income (Mezzanine)	354								354
Distributions (Mezzanine)	(354)								(354)
Noncontrolling Interest - Operating Partnership (Mezzanine) - Ending Balance at Sep. 30, 2018	$ 7,537								$ 7,537