Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
ASSETS
Land and land improvements	$ 1,187,786	$ 1,189,760
Building and improvements	5,347,120	5,343,908
Less accumulated depreciation	(1,221,059)	(1,182,569)
Operating real estate	5,313,847	5,351,099
Development in progress	269,518	277,411
Land held for development	272,349	269,059
Net real estate	5,855,714	5,897,569
Cash and cash equivalents	38,755	69,346
Restricted cash	18,911	20,325
Accounts receivable	19,039	15,481
Deferred rent receivable	113,129	107,909
Deferred financing and leasing costs, net of accumulated amortization (2015, $173,076; 2014, $169,468)	202,231	206,286
Investments in and advances to unconsolidated joint ventures	215,403	208,832
Assets held for sale	0	8,389
Prepaid expenses and other assets	101,322	91,399
Total assets	6,564,504	6,625,536
LIABILITIES
Mortgage loans	484,584	487,301
Unsecured notes	2,607,874	2,509,094
Credit facility	50,000	167,000
Accounts payable	51,783	52,043
Accrued interest	36,691	24,513
Dividend and distributions payable	72,512	72,253
Other liabilities	199,311	219,418
Total liabilities	3,502,755	3,531,622
Noncontrolling interest - operating partnership - 301,483 preferred units outstanding as of March 31, 2015 and December 31, 2014	7,537	7,537
EQUITY
Common shares of beneficial interest, $.001 par value, 283,987,000 shares authorized; 150,367,813 (includes 1,249,909 in treasury) and 149,807,179 (includes 1,249,909 in treasury) shares issued and outstanding as of March 31, 2015 and December 31, 2014, respectively	150	150
Additional paid-in capital	3,760,834	3,740,594
Accumulated other comprehensive loss	(17,346)	(6,252)
Distributions in excess of net income	(694,748)	(654,869)
Common shares in treasury, at cost, 1,249,909 shares as of March 31, 2015 and December 31, 2014	(51,951)	(51,951)
Total Liberty Property Trust shareholders' equity	2,996,939	3,027,672
Noncontrolling interest - operating partnership
Noncontrolling interest - operating partnerships	53,354	54,786
Noncontrolling interest - consolidated joint ventures	3,919	3,919
Total equity	3,054,212	3,086,377
Total liabilities, noncontrolling interest - operating partnership and equity	6,564,504	6,625,536
Liberty Property Limited Partnership [Member]
ASSETS
Land and land improvements	1,187,786	1,189,760
Building and improvements	5,347,120	5,343,908
Less accumulated depreciation	(1,221,059)	(1,182,569)
Operating real estate	5,313,847	5,351,099
Development in progress	269,518	277,411
Land held for development	272,349	269,059
Net real estate	5,855,714	5,897,569
Cash and cash equivalents	38,755	69,346
Restricted cash	18,911	20,325
Accounts receivable	19,039	15,481
Deferred rent receivable	113,129	107,909
Deferred financing and leasing costs, net of accumulated amortization (2015, $173,076; 2014, $169,468)	202,231	206,286
Investments in and advances to unconsolidated joint ventures	215,403	208,832
Assets held for sale	0	8,389
Prepaid expenses and other assets	101,322	91,399
Total assets	6,564,504	6,625,536
LIABILITIES
Mortgage loans	484,584	487,301
Unsecured notes	2,607,874	2,509,094
Credit facility	50,000	167,000
Accounts payable	51,783	52,043
Accrued interest	36,691	24,513
Dividend and distributions payable	72,512	72,253
Other liabilities	199,311	219,418
Total liabilities	3,502,755	3,531,622
Noncontrolling interest - operating partnership - 301,483 preferred units outstanding as of March 31, 2015 and December 31, 2014	7,537	7,537
EQUITY
General partner’s equity - 149,117,904 (net of 1,249,909 treasury units) and 148,557,270 (net of 1,249,909 treasury units) common units outstanding as of March 31, 2015 and December 31, 2014, respectively	2,996,939	3,027,672
Limited partners' equity	53,354	54,786
Noncontrolling interest - operating partnership
Noncontrolling interest - consolidated joint ventures	3,919	3,919
Total equity	3,054,212	3,086,377
Total liabilities, noncontrolling interest - operating partnership and equity	$ 6,564,504	$ 6,625,536