Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Real Estate [Abstract]
Land and land improvements	$ 1,149,886	$ 1,046,571
Building and improvements	4,445,617	4,189,319
Less accumulated depreciation	(935,363)	(880,004)
Operating real estate	4,660,140	4,355,886
Development in progress	330,755	333,437
Land held for development	351,366	330,748
Net real estate	5,342,261	5,020,071
Cash and cash equivalents	24,211	11,882
Restricted cash	14,865	13,803
Accounts receivable, net	9,378	10,402
Deferred rent receivable, net	118,834	109,014
Deferred financing and leasing costs, net of accumulated amortization (June 30, 2018, $158,817; December 31, 2017, $155,865)	150,903	148,583
Investments in and advances to unconsolidated joint ventures	359,776	288,456
Assets held for sale	376,551	547,668
Prepaid expenses and other assets	154,094	289,878
Total assets	6,550,873	6,439,757
LIABILITIES
Mortgage loans, net	235,753	267,093
Unsecured notes, net	2,284,882	2,283,513
Credit facility	394,223	358,939
Accounts payable	72,988	77,000
Accrued interest	22,081	21,796
Distributions payable	60,528	60,330
Other liabilities	273,135	204,005
Liabilities held for sale	2,521	11,178
Total liabilities	3,346,111	3,283,854
Noncontrolling interest - operating partnership - 301,483 preferred units outstanding as of June 30, 2018 and December 31, 2017	7,537	7,537
EQUITY
Common shares of beneficial interest, $.001 par value, 283,987,000 shares authorized; 147,796,618 and 147,450,691 shares issued and outstanding as of June 30, 2018 and December 31, 2017, respectively	148	147
Additional paid-in capital	3,686,505	3,674,978
Accumulated other comprehensive loss	(43,383)	(37,797)
Distributions in excess of net income	(508,386)	(549,970)
Total Liberty Property Trust shareholders' equity	3,134,884	3,087,358
Noncontrolling interest - operating partnership
Noncontrolling interest – operating partnership - 3,520,205 common units outstanding as of June 30, 2018 and December 31, 2017	56,918	56,159
Noncontrolling interest - consolidated joint ventures	5,423	4,849
Total owners' equity	3,197,225	3,148,366
Total liabilities, noncontrolling interest - operating partnership and equity	6,550,873	6,439,757
Liberty Property Limited Partnership [Member]
Real Estate [Abstract]
Land and land improvements	1,149,886	1,046,571
Building and improvements	4,445,617	4,189,319
Less accumulated depreciation	(935,363)	(880,004)
Operating real estate	4,660,140	4,355,886
Development in progress	330,755	333,437
Land held for development	351,366	330,748
Net real estate	5,342,261	5,020,071
Cash and cash equivalents	24,211	11,882
Restricted cash	14,865	13,803
Accounts receivable, net	9,378	10,402
Deferred rent receivable, net	118,834	109,014
Deferred financing and leasing costs, net of accumulated amortization (June 30, 2018, $158,817; December 31, 2017, $155,865)	150,903	148,583
Investments in and advances to unconsolidated joint ventures	359,776	288,456
Assets held for sale	376,551	547,668
Prepaid expenses and other assets	154,094	289,878
Total assets	6,550,873	6,439,757
LIABILITIES
Mortgage loans, net	235,753	267,093
Unsecured notes, net	2,284,882	2,283,513
Credit facility	394,223	358,939
Accounts payable	72,988	77,000
Accrued interest	22,081	21,796
Distributions payable	60,528	60,330
Other liabilities	273,135	204,005
Liabilities held for sale	2,521	11,178
Total liabilities	3,346,111	3,283,854
Noncontrolling interest - operating partnership - 301,483 preferred units outstanding as of June 30, 2018 and December 31, 2017	7,537	7,537
EQUITY
General partner’s equity - 147,796,618 and 147,450,691 common units outstanding as of June 30, 2018 and December 31, 2017, respectively	3,134,884	3,087,358
Limited partners’ equity – 3,520,205 common units outstanding as of June 30, 2018 and December 31, 2017	56,918	56,159
Noncontrolling interest - operating partnership
Noncontrolling interest - consolidated joint ventures	5,423	4,849
Total owners' equity	3,197,225	3,148,366
Total liabilities, noncontrolling interest - operating partnership and equity	$ 6,550,873	$ 6,439,757