Consolidated Balance Sheets (USD $)	Sep. 30, 2014	Dec. 31, 2013
ASSETS
Land and land improvements	$ 1,195,924,000	$ 1,138,922,000
Building and improvements	5,413,512,000	5,142,480,000
Less accumulated depreciation	(1,177,726,000)	(1,057,644,000)
Operating real estate	5,431,710,000	5,223,758,000
Development in progress	250,506,000	209,187,000
Land held for development	265,864,000	233,055,000
Net real estate	5,948,080,000	5,666,000,000
Cash and cash equivalents	39,086,000	163,414,000
Restricted cash	22,918,000	51,456,000
Accounts receivable	18,571,000	13,900,000
Deferred rent receivable	111,823,000	99,956,000
Deferred financing and leasing costs, net of accumulated amortization (2014, $167,045; 2013, $140,933)	217,261,000	226,377,000
Investments in and advances to unconsolidated joint ventures	202,570,000	179,655,000
Assets held for sale	2,895,000	278,962,000
Prepaid expenses and other assets	97,638,000	95,840,000
Total assets	6,660,842,000	6,775,560,000
LIABILITIES
Mortgage loans	534,547,000	545,306,000
Unsecured notes	2,508,886,000	2,708,213,000
Credit facility	140,950,000	0
Accounts payable	65,668,000	70,406,000
Accrued interest	41,277,000	25,777,000
Dividend and distributions payable	72,046,000	71,323,000
Other liabilities	221,943,000	250,819,000
Total liabilities	3,585,317,000	3,671,844,000
Noncontrolling interest - operating partnership - 301,483 preferred units outstanding as of September 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; 149,354,294 (includes 1,249,909 in treasury) and 147,846,801 (includes 1,249,909 in treasury) shares issued and outstanding as of September 30, 2014 and December 31, 2013, respectively	149,000	148,000
Additional paid-in capital	3,724,184,000	3,669,618,000
Accumulated other comprehensive loss	3,707,000	9,742,000
Distributions in excess of net income	(666,646,000)	(591,713,000)
Common shares in treasury, at cost, 1,249,909 shares as of September 30, 2014 and December 31, 2013	(51,951,000)	(51,951,000)
Total Liberty Property Trust shareholders' equity	3,009,443,000	3,035,844,000
Noncontrolling interest - operating partnership
Noncontrolling interest - operating partnerships	54,626,000	56,713,000
Noncontrolling interest - consolidated joint ventures	3,919,000	3,622,000
Total equity	3,067,988,000	3,096,179,000
Total liabilities, noncontrolling interest - operating partnership and equity	6,660,842,000	6,775,560,000
Liberty Property Limited Partnership [Member]
ASSETS
Land and land improvements	1,195,924,000	1,138,922,000
Building and improvements	5,413,512,000	5,142,480,000
Less accumulated depreciation	(1,177,726,000)	(1,057,644,000)
Operating real estate	5,431,710,000	5,223,758,000
Development in progress	250,506,000	209,187,000
Land held for development	265,864,000	233,055,000
Net real estate	5,948,080,000	5,666,000,000
Cash and cash equivalents	39,086,000	163,414,000
Restricted cash	22,918,000	51,456,000
Accounts receivable	18,571,000	13,900,000
Deferred rent receivable	111,823,000	99,956,000
Deferred financing and leasing costs, net of accumulated amortization (2014, $167,045; 2013, $140,933)	217,261,000	226,377,000
Investments in and advances to unconsolidated joint ventures	202,570,000	179,655,000
Assets held for sale	2,895,000	278,962,000
Prepaid expenses and other assets	97,638,000	95,840,000
Total assets	6,660,842,000	6,775,560,000
LIABILITIES
Mortgage loans	534,547,000	545,306,000
Unsecured notes	2,508,886,000	2,708,213,000
Credit facility	140,950,000	0
Accounts payable	65,668,000	70,406,000
Accrued interest	41,277,000	25,777,000
Dividend and distributions payable	72,046,000	71,323,000
Other liabilities	221,943,000	250,819,000
Total liabilities	3,585,317,000	3,671,844,000
Noncontrolling interest - operating partnership - 301,483 preferred units outstanding as of September 30, 2014 and December 31, 2013	7,537,000	7,537,000
EQUITY
General partner’s equity - 148,104,385 (net of 1,249,909 treasury units) and 146,596,892 (net of 1,249,909 treasury units) common units outstanding as of September 30, 2014 and December 31, 2013, respectively	3,009,443,000	3,035,844,000
Limited partners' equity	54,626,000	56,713,000
Noncontrolling interest - operating partnership
Noncontrolling interest - consolidated joint ventures	3,919,000	3,622,000
Total equity	3,067,988,000	3,096,179,000
Total liabilities, noncontrolling interest - operating partnership and equity	$ 6,660,842,000	$ 6,775,560,000