Consolidated Statements of Equity - USD ($) $ in Thousands	Total	COMMON SHARES OF BENEFICIAL INTEREST	ADDITIONAL PAID-IN CAPITAL	ACCUMULATED OTHER COMPREHENSIVE LOSS	DISTRIBUTIONS IN EXCESS OF NET INCOME	TOTAL LIBERTY PROPERTY TRUST SHAREHOLDERS’ EQUITY	NONCONTROLLING INTEREST - OPERATING PARTNERSHIP	NONCONTROLLING INTEREST - CONSOLIDATED JOINT VENTURES	Common shares	Liberty Property Limited Partnership	Liberty Property Limited Partnership GENERAL PARTNER	Liberty Property Limited Partnership LIMITED PARTNER	Liberty Property Limited Partnership NONCONTROLLING INTEREST - CONSOLIDATED JOINT VENTURES	Liberty Property Limited Partnership TOTAL OWNERS’ EQUITY	Liberty Property Limited Partnership Common Units GENERAL PARTNER	Liberty Property Limited Partnership Common Units LIMITED PARTNER	Liberty Property Limited Partnership, Preferred Activity
Common shares outstanding - Beginning Balance (shares) at Dec. 31, 2017									147,450,691
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
Beginning balance at Dec. 31, 2017	$ 3,148,366	$ 147	$ 3,674,978	$ (37,797)	$ (549,970)	$ 3,087,358	$ 56,159	$ 4,849			$ 3,087,358	$ 56,159	$ 4,849	$ 3,148,366
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			309,938	7,384	1,010	318,332
Net income available to common shareholders	309,938									$ 317,322
Contributions from partners											13,654			13,654
Contributions from partners (units)															361,630
Distributions to partners											(177,325)	(4,283)	(432)	(182,040)
Distributions	(182,040)				(177,325)	(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)		(9,221)
Other comprehensive income (loss) - derivative instruments	493			482		482	11			493	482	11		493
Common shares outstanding - Ending Balance (shares) at Sep. 30, 2018									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
Ending balance at Sep. 30, 2018	3,289,584	148	3,688,631	(46,322)	(417,357)	3,225,100	59,057	5,427			3,225,100	59,057	5,427	3,289,584
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	(354)																(354)
Noncontrolling Interest - Operating Partnership (Mezzanine) - Ending Balance at Sep. 30, 2018	7,537																7,537
Common shares outstanding - Beginning Balance (shares) at Jun. 30, 2018									147,796,618
General Partner's units outstanding - Beginning Balance (units) at Jun. 30, 2018															147,796,618
Limited Partners' units outstanding - Beginning Balance (units) at Jun. 30, 2018																3,520,205
Beginning balance at Jun. 30, 2018	3,197,225	148	3,686,505	(43,383)	(508,386)	3,134,884	56,918	5,423			3,134,884	56,918	5,423	3,197,225
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net proceeds from the issuance of common shares	728	0	728			728
Net proceeds from issuance of common shares (shares)									15,703
Net income	153,953				150,143	150,143	3,578	232			150,143	3,578	232	153,953
Net income available to common shareholders	150,143									153,721
Contributions from partners											2,126			2,126
Contributions from partners (units)															15,703
Distributions to partners											(59,114)	(1,369)	(228)	(60,711)
Distributions	(60,711)				(59,114)	(59,114)	(1,369)	(228)
Share-based compensation	1,398		1,398			1,398
Other comprehensive loss - foreign currency translation activity	(3,015)			(2,945)		(2,945)	(70)			(3,015)	(2,945)	(70)		(3,015)
Other comprehensive income (loss) - derivative instruments	6			6		6				$ 6	6	0		6
Common shares outstanding - Ending Balance (shares) at Sep. 30, 2018									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
Ending balance at Sep. 30, 2018	3,289,584	148	3,688,631	(46,322)	(417,357)	3,225,100	59,057	5,427			3,225,100	59,057	5,427	3,289,584
Noncontrolling Interest - Operating Partnership (Mezzanine) - Beginning Balance at Jun. 30, 2018	7,537																7,537
Increase (Decrease) in Temporary Equity [Roll Forward]
Net income (Mezzanine)	118																118
Distributions	(118)																(118)
Noncontrolling Interest - Operating Partnership (Mezzanine) - Ending Balance at Sep. 30, 2018	$ 7,537																7,537
Common shares outstanding - Beginning Balance (shares) at Dec. 31, 2018	147,899,354								147,899,354	147,899,354
General Partner's units outstanding - Beginning Balance (units) at Dec. 31, 2018															147,899,354
Limited Partners' units outstanding - Beginning Balance (units) at Dec. 31, 2018	3,520,205									3,520,205						3,520,205
Beginning balance at Dec. 31, 2018	$ 3,396,772	148	3,691,778	(55,243)	(306,822)	3,329,861	61,471	5,440		$ 3,396,772	3,329,861	61,471	5,440	3,396,772
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net proceeds from the issuance of common shares	462,117	10	462,107	0	0	462,117	0	0
Net proceeds from issuance of common shares (shares)									9,830,088
Net income	260,510	0	0	0			5,875	170			254,464	5,875	170	260,509
Net income available to common shareholders	254,465					254,465				260,340
Contributions from partners											466,945	0	0	466,945
Contributions from partners (units)															9,830,088
Distributions to partners											(186,271)	(4,371)	(167)	(190,809)
Distributions	(190,810)	0	0	0	(186,272)	(186,272)	(4,371)	(167)
Share-based compensation	4,828	0	4,828	0	0	4,828	0	0
Other comprehensive loss - foreign currency translation activity	(7,574)	0	0	(7,410)	0	(7,410)	(164)	0		(7,574)	(7,410)	(164)	0	(7,574)
Other comprehensive income (loss) - derivative instruments	(1,887)	0	0	(1,843)	0	(1,843)	(44)	0		$ (1,887)	(1,843)	(44)	0	(1,887)
Acquisition of noncontrolling interest	$ (18,513)	0	(13,350)	0	0	(13,350)	0	(5,163)			(13,350)	0	(5,163)	(18,513)		$ 0
Redemption of noncontrolling interests - common units (shares)									26,156						26,156
Redemption of noncontrolling interest - common units		0	459	0	0	459	(459)	0
Redemption of limited partners common units for common shares											459	(459)
Redemption of limited partners common units for common shares (units)																(26,156)
Common shares outstanding - Ending Balance (shares) at Sep. 30, 2019	157,755,598								157,755,598	157,755,598
General Partner's units outstanding - Ending Balance (units) at Sep. 30, 2019															157,755,598
Limited Partners' units outstanding - Ending Balance (units) at Sep. 30, 2019	3,500,000									3,500,000						3,494,049
Ending balance at Sep. 30, 2019	$ 3,905,443	158	4,145,822	(64,496)	(238,629)	3,842,855	62,308	280		$ 3,905,443	3,842,855	62,308	280	3,905,443
Noncontrolling Interest - Operating Partnership (Mezzanine) - Beginning Balance at Dec. 31, 2018	7,537									7,537							7,537
Increase (Decrease) in Temporary Equity [Roll Forward]
Net income (Mezzanine)	251																251
Distributions	(251)																(251)
Temporary Equity Decrease from Redemption of Units	(2,200)																(2,200)
Noncontrolling Interest - Operating Partnership (Mezzanine) - Ending Balance at Sep. 30, 2019	5,337									5,337							5,337
Common shares outstanding - Beginning Balance (shares) at Jun. 30, 2019									148,258,042
General Partner's units outstanding - Beginning Balance (units) at Jun. 30, 2019															148,258,042
Limited Partners' units outstanding - Beginning Balance (units) at Jun. 30, 2019																3,513,049
Beginning balance at Jun. 30, 2019	3,417,364	148	3,687,085	(57,674)	(274,311)	3,355,248	61,839	277			3,355,248	61,839	277	3,417,364
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net proceeds from the issuance of common shares	457,118	10	457,108	0	0	457,118	0	0
Net proceeds from issuance of common shares (shares)									9,478,556
Net income	102,593	0	0	0	100,364	100,364	2,226	3			100,364	2,226	3	102,593
Net income available to common shareholders	100,364									102,590
Contributions from partners											458,413	0	0	458,413
Contributions from partners (units)															9,478,556
Distributions to partners											(64,682)	(1,272)	0	(65,954)
Distributions	(65,954)	0	0	0	(64,682)	(64,682)	(1,272)	0
Share-based compensation	1,295	0	1,295	0	0	1,295	0	0
Other comprehensive loss - foreign currency translation activity	(7,056)	0	0	(6,903)	0	(6,903)	(153)	0		(7,056)	(6,903)	(153)	0	(7,056)
Other comprehensive income (loss) - derivative instruments	83	0	0	81	0	81	2	0		$ 83	81	2	0	83
Redemption of noncontrolling interests - common units (shares)									19,000						19,000
Redemption of noncontrolling interest - common units	$ 0	0	334	0	0	334	(334)	0
Redemption of limited partners common units for common shares											334	(334)
Redemption of limited partners common units for common shares (units)																(19,000)
Common shares outstanding - Ending Balance (shares) at Sep. 30, 2019	157,755,598								157,755,598	157,755,598
General Partner's units outstanding - Ending Balance (units) at Sep. 30, 2019															157,755,598
Limited Partners' units outstanding - Ending Balance (units) at Sep. 30, 2019	3,500,000									3,500,000						3,494,049
Ending balance at Sep. 30, 2019	$ 3,905,443	$ 158	$ 4,145,822	$ (64,496)	$ (238,629)	$ 3,842,855	$ 62,308	$ 280		$ 3,905,443	$ 3,842,855	$ 62,308	$ 280	$ 3,905,443
Noncontrolling Interest - Operating Partnership (Mezzanine) - Beginning Balance at Jun. 30, 2019	5,337																5,337
Increase (Decrease) in Temporary Equity [Roll Forward]
Net income (Mezzanine)	83																83
Distributions	(83)																(83)
Noncontrolling Interest - Operating Partnership (Mezzanine) - Ending Balance at Sep. 30, 2019	$ 5,337									$ 5,337							$ 5,337