Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Real Estate [Abstract]
Land and land improvements	$ 1,081,447	$ 1,094,470
Building and improvements	4,539,552	4,501,921
Less accumulated depreciation	(1,015,786)	(940,115)
Operating real estate	4,605,213	4,656,276
Development in progress	395,089	267,450
Land held for development	331,340	336,569
Net real estate	5,331,642	5,260,295
Cash and cash equivalents	47,666	43,642
Restricted cash	16,824	12,383
Accounts receivable	13,258	13,994
Deferred rent receivable	123,718	109,245
Deferred financing and leasing costs, net of accumulated amortization (September 30, 2017, $168,173; December 31, 2016, $152,309)	154,147	153,393
Investments in and advances to unconsolidated joint ventures	283,803	245,078
Assets held for sale	177,549	4,548
Prepaid expenses and other assets	161,067	150,235
Total assets	6,309,674	5,992,813
LIABILITIES
Mortgage loans	269,380	276,650
Unsecured notes	2,282,828	2,280,286
Credit facility	295,000	0
Accounts payable	78,384	65,914
Accrued interest	34,707	21,878
Dividend and distributions payable	60,131	71,501
Other liabilities	209,710	206,124
Total liabilities	3,230,140	2,922,353
Noncontrolling interest - operating partnership - 301,483 preferred units outstanding as of September 30, 2017 and December 31, 2016	7,537	7,537
EQUITY
Common shares of beneficial interest, $.001 par value, 283,987,000 shares authorized; 147,399,264 and 146,993,018 shares issued and outstanding as of September 30, 2017 and December 31, 2016, respectively	147	147
Additional paid-in capital	3,671,758	3,655,910
Accumulated other comprehensive loss	(39,741)	(56,031)
Distributions in excess of net income	(619,350)	(596,635)
Total Liberty Property Trust shareholders' equity	3,012,814	3,003,391
Noncontrolling interest - operating partnership
Noncontrolling interest - operating partnerships	54,525	54,631
Noncontrolling interest - consolidated joint ventures	4,658	4,901
Total owners' equity	3,071,997	3,062,923
Total liabilities, noncontrolling interest - operating partnership and equity	6,309,674	5,992,813
Liberty Property Limited Partnership [Member]
Real Estate [Abstract]
Land and land improvements	1,081,447	1,094,470
Building and improvements	4,539,552	4,501,921
Less accumulated depreciation	(1,015,786)	(940,115)
Operating real estate	4,605,213	4,656,276
Development in progress	395,089	267,450
Land held for development	331,340	336,569
Net real estate	5,331,642	5,260,295
Cash and cash equivalents	47,666	43,642
Restricted cash	16,824	12,383
Accounts receivable	13,258	13,994
Deferred rent receivable	123,718	109,245
Deferred financing and leasing costs, net of accumulated amortization (September 30, 2017, $168,173; December 31, 2016, $152,309)	154,147	153,393
Investments in and advances to unconsolidated joint ventures	283,803	245,078
Assets held for sale	177,549	4,548
Prepaid expenses and other assets	161,067	150,235
Total assets	6,309,674	5,992,813
LIABILITIES
Mortgage loans	269,380	276,650
Unsecured notes	2,282,828	2,280,286
Credit facility	295,000	0
Accounts payable	78,384	65,914
Accrued interest	34,707	21,878
Dividend and distributions payable	60,131	71,501
Other liabilities	209,710	206,124
Total liabilities	3,230,140	2,922,353
Noncontrolling interest - operating partnership - 301,483 preferred units outstanding as of September 30, 2017 and December 31, 2016	7,537	7,537
EQUITY
General partner’s equity - 147,399,264 and 146,993,018 common units outstanding as of September 30, 2017 and December 31, 2016, respectively	3,012,814	3,003,391
Limited partners' equity	54,525	54,631
Noncontrolling interest - operating partnership
Noncontrolling interest - consolidated joint ventures	4,658	4,901
Total owners' equity	3,071,997	3,062,923
Total liabilities, noncontrolling interest - operating partnership and equity	$ 6,309,674	$ 5,992,813