Consolidated Balance Sheets (USD $)	Jun. 30, 2014	Dec. 31, 2013
ASSETS
Land and land improvements	$ 1,162,397,000	$ 1,139,455,000
Building and improvements	5,244,783,000	5,144,758,000
Less accumulated depreciation	(1,135,864,000)	(1,057,680,000)
Operating real estate	5,271,316,000	5,226,533,000
Development in progress	329,685,000	209,187,000
Land held for development	241,196,000	233,055,000
Net real estate	5,842,197,000	5,668,775,000
Cash and cash equivalents	228,678,000	163,414,000
Restricted cash	18,980,000	51,456,000
Accounts receivable	15,272,000	13,900,000
Deferred rent receivable	107,473,000	99,956,000
Deferred financing and leasing costs, net of accumulated amortization (2014, $158,313; 2013, $140,958)	221,121,000	226,607,000
Investments in and advances to unconsolidated joint ventures	203,876,000	179,655,000
Assets held for sale	0	275,957,000
Prepaid expenses and other assets	94,142,000	95,840,000
Total assets	6,731,739,000	6,775,560,000
LIABILITIES
Mortgage loans	537,338,000	545,306,000
Unsecured notes	2,708,668,000	2,708,213,000
Credit facility	0	0
Accounts payable	56,073,000	70,406,000
Accrued interest	28,530,000	25,777,000
Dividend and distributions payable	71,864,000	71,323,000
Other liabilities	219,050,000	250,819,000
Total liabilities	3,621,523,000	3,671,844,000
Noncontrolling interest - operating partnership - 301,483 preferred units outstanding as of June 30, 2014 and December 31, 2013	7,537,000	7,537,000
EQUITY
Common shares of beneficial interest, $.001 par value, 283,987,000 shares authorized; 149,008,030 (includes 1,249,909 in treasury) and 147,846,801 (includes 1,249,909 in treasury) shares issued and outstanding as of June 30, 2014 and December 31, 2013, respectively	149,000	148,000
Additional paid-in capital	3,709,753,000	3,669,618,000
Accumulated other comprehensive loss	15,752,000	9,742,000
Distributions in excess of net income	(630,706,000)	(591,713,000)
Common shares in treasury, at cost, 1,249,909 shares as of June 30, 2014 and December 31, 2013	(51,951,000)	(51,951,000)
Total Liberty Property Trust shareholders' equity	3,042,997,000	3,035,844,000
Noncontrolling interest - operating partnership
Noncontrolling interest - consolidated joint ventures	3,919,000	3,622,000
Total equity	3,102,679,000	3,096,179,000
Total liabilities, noncontrolling interest - operating partnership and equity	6,731,739,000	6,775,560,000
Limited partners’ equity – 3,553,566 and 3,556,556 common units outstanding as of June 30, 2014 and December 31, 2013, respectively
Noncontrolling interest - operating partnership
Noncontrolling interest - operating partnerships	55,763,000	56,713,000
Liberty Property Limited Partnership [Member]
ASSETS
Land and land improvements	1,162,397,000	1,139,455,000
Building and improvements	5,244,783,000	5,144,758,000
Less accumulated depreciation	(1,135,864,000)	(1,057,680,000)
Operating real estate	5,271,316,000	5,226,533,000
Development in progress	329,685,000	209,187,000
Land held for development	241,196,000	233,055,000
Net real estate	5,842,197,000	5,668,775,000
Cash and cash equivalents	228,678,000	163,414,000
Restricted cash	18,980,000	51,456,000
Accounts receivable	15,272,000	13,900,000
Deferred rent receivable	107,473,000	99,956,000
Deferred financing and leasing costs, net of accumulated amortization (2014, $158,313; 2013, $140,958)	221,121,000	226,607,000
Investments in and advances to unconsolidated joint ventures	203,876,000	179,655,000
Assets held for sale	0	275,957,000
Prepaid expenses and other assets	94,142,000	95,840,000
Total assets	6,731,739,000	6,775,560,000
LIABILITIES
Mortgage loans	537,338,000	545,306,000
Unsecured notes	2,708,668,000	2,708,213,000
Credit facility	0	0
Accounts payable	56,073,000	70,406,000
Accrued interest	28,530,000	25,777,000
Dividend and distributions payable	71,864,000	71,323,000
Other liabilities	219,050,000	250,819,000
Total liabilities	3,621,523,000	3,671,844,000
Noncontrolling interest - operating partnership - 301,483 preferred units outstanding as of June 30, 2014 and December 31, 2013	7,537,000	7,537,000
EQUITY
General partner’s equity - 147,758,121 (net of 1,249,909 treasury units) and 146,596,892 (net of 1,249,909 treasury units) common units outstanding as of June 30, 2014 and December 31, 2013, respectively	3,042,997,000	3,035,844,000
Noncontrolling interest - operating partnership
Noncontrolling interest - consolidated joint ventures	3,919,000	3,622,000
Total equity	3,102,679,000	3,096,179,000
Total liabilities, noncontrolling interest - operating partnership and equity	6,731,739,000	6,775,560,000
Liberty Property Limited Partnership [Member] | Limited partners’ equity – 3,553,566 and 3,556,556 common units outstanding as of June 30, 2014 and December 31, 2013, respectively
EQUITY
Limited partners' equity	$ 55,763,000	$ 56,713,000