Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Real Estate [Abstract]
Land and land improvements	$ 1,180,071	$ 1,138,337
Building and improvements	4,448,883	4,358,264
Less accumulated depreciation	(962,688)	(933,173)
Operating real estate	4,666,266	4,563,428
Development in progress	373,154	333,437
Land held for development	316,226	330,748
Net real estate	5,355,646	5,227,613
Cash and cash equivalents	30,380	11,882
Restricted cash	9,366	13,803
Accounts receivable	12,767	11,231
Deferred rent receivable	117,776	113,282
Deferred financing and leasing costs, net of accumulated amortization (March 31, 2018, $168,754; December 31, 2017, $164,755)	151,530	152,471
Investments in and advances to unconsolidated joint ventures	350,458	288,456
Assets held for sale	238,199	330,186
Prepaid expenses and other assets	148,509	290,833
Total assets	6,414,631	6,439,757
LIABILITIES
Mortgage loans	264,906	267,093
Unsecured notes	2,284,197	2,283,513
Credit facility	257,175	358,939
Accounts payable	68,499	77,625
Accrued interest	34,855	21,796
Dividend and distributions payable	60,518	60,330
Other liabilities	186,807	205,055
Liabilities held for sale	1,849	9,503
Total liabilities	3,158,806	3,283,854
Noncontrolling interest - operating partnership - 301,483 preferred units outstanding as of March 31, 2018 and December 31, 2017	7,537	7,537
EQUITY
Common shares of beneficial interest, $.001 par value, 283,987,000 shares authorized; 147,773,141 and 147,450,691 shares issued and outstanding as of March 31, 2018 and December 31, 2017, respectively	148	147
Additional paid-in capital	3,683,660	3,674,978
Accumulated other comprehensive loss	(29,674)	(37,797)
Distributions in excess of net income	(468,883)	(549,970)
Total Liberty Property Trust shareholders' equity	3,185,251	3,087,358
Noncontrolling interest - operating partnership
Noncontrolling interest - operating partnerships	58,186	56,159
Noncontrolling interest - consolidated joint ventures	4,851	4,849
Total owners' equity	3,248,288	3,148,366
Total liabilities, noncontrolling interest - operating partnership and equity	6,414,631	6,439,757
Liberty Property Limited Partnership [Member]
Real Estate [Abstract]
Land and land improvements	1,180,071	1,138,337
Building and improvements	4,448,883	4,358,264
Less accumulated depreciation	(962,688)	(933,173)
Operating real estate	4,666,266	4,563,428
Development in progress	373,154	333,437
Land held for development	316,226	330,748
Net real estate	5,355,646	5,227,613
Cash and cash equivalents	30,380	11,882
Restricted cash	9,366	13,803
Accounts receivable	12,767	11,231
Deferred rent receivable	117,776	113,282
Deferred financing and leasing costs, net of accumulated amortization (March 31, 2018, $168,754; December 31, 2017, $164,755)	151,530	152,471
Investments in and advances to unconsolidated joint ventures	350,458	288,456
Assets held for sale	238,199	330,186
Prepaid expenses and other assets	148,509	290,833
Total assets	6,414,631	6,439,757
LIABILITIES
Mortgage loans	264,906	267,093
Unsecured notes	2,284,197	2,283,513
Credit facility	257,175	358,939
Accounts payable	68,499	77,625
Accrued interest	34,855	21,796
Dividend and distributions payable	60,518	60,330
Other liabilities	186,807	205,055
Liabilities held for sale	1,849	9,503
Total liabilities	3,158,806	3,283,854
Noncontrolling interest - operating partnership - 301,483 preferred units outstanding as of March 31, 2018 and December 31, 2017	7,537	7,537
EQUITY
General partner’s equity - 147,773,141 and 147,450,691 common units outstanding as of March 31, 2018 and December 31, 2017, respectively	3,185,251	3,087,358
Limited partners' equity	58,186	56,159
Noncontrolling interest - operating partnership
Noncontrolling interest - consolidated joint ventures	4,851	4,849
Total owners' equity	3,248,288	3,148,366
Total liabilities, noncontrolling interest - operating partnership and equity	$ 6,414,631	$ 6,439,757