Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
OPERATING ACTIVITIES
Net income	$ 139,664	$ 147,847
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	176,207	137,302
Amortization of deferred financing costs	3,727	2,952
Equity in earnings of unconsolidated joint ventures	(7,297)	(3,973)
Distributions from unconsolidated joint ventures	0	613
Gain on property dispositions	(48,170)	(49,367)
Share-based compensation	10,422	8,174
Other	(5,202)	(6,248)
Changes in operating assets and liabilities:
Restricted cash	28,469	(2,703)
Accounts receivable	(4,771)	231
Deferred rent receivable	(11,928)	(6,171)
Prepaid expenses and other assets	(38,882)	(50,389)
Accounts payable	18,824	15,494
Accrued interest	15,500	18,922
Other liabilities	(26,232)	2,352
Net cash provided by operating activities	250,331	215,036
INVESTING ACTIVITIES
Investment in operating properties - acquisitions	(97,677)	(161,404)
Investment in operating properties - other	(61,480)	(40,433)
Investments in and advances to unconsolidated joint ventures	(13,894)	(11,736)
Distributions from unconsolidated joint ventures	10,213	6,825
Net proceeds from disposition of properties/land	351,301	134,024
Net proceeds from public reimbursement receivable/escrow	5,501	12,943
Investment in development in progress	(222,484)	(81,736)
Investment in land held for development	(73,547)	(34,642)
Investment in deferred leasing costs	(28,409)	(22,996)
Net cash used in investing activities	(130,476)	(199,155)
FINANCING ACTIVITIES
Net proceeds from issuance of common shares	44,097	954,481
Redemption of preferred units	0	(64,500)
Proceeds from unsecured notes	0	448,646
Redemption of unsecured notes	(200,000)	0
Proceeds from mortgage loans	0	10,401
Repayments of mortgage loans	(9,329)	(3,977)
Proceeds from credit facility	179,750	344,050
Repayments on credit facility	(38,800)	(436,050)
Payment of deferred financing costs	(3,622)	(3,883)
Distribution paid on common shares	(209,779)	(170,970)
Distribution paid on units/to consolidated joint venture partners	(5,692)	(7,619)
Net cash (used in) provided by financing activities	(243,375)	1,070,579
Net (decrease) increase in cash and cash equivalents	(123,520)	1,086,460
Decrease in cash and cash equivalents related to foreign currency translation	(808)	(246)
Cash and cash equivalents at beginning of period	163,414	38,356
Cash and cash equivalents at end of period	39,086	1,124,570
Liberty Property Limited Partnership [Member]
OPERATING ACTIVITIES
Net income	139,664	147,847
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	176,207	137,302
Amortization of deferred financing costs	3,727	2,952
Equity in earnings of unconsolidated joint ventures	(7,297)	(3,973)
Distributions from unconsolidated joint ventures	0	613
Gain on property dispositions	(48,170)	(49,367)
Share-based compensation	10,422	8,174
Other	(5,202)	(6,248)
Changes in operating assets and liabilities:
Restricted cash	28,469	(2,703)
Accounts receivable	(4,771)	231
Deferred rent receivable	(11,928)	(6,171)
Prepaid expenses and other assets	(38,882)	(50,389)
Accounts payable	18,824	15,494
Accrued interest	15,500	18,922
Other liabilities	(26,232)	2,352
Net cash provided by operating activities	250,331	215,036
INVESTING ACTIVITIES
Investment in operating properties - acquisitions	(97,677)	(161,404)
Investment in operating properties - other	(61,480)	(40,433)
Investments in and advances to unconsolidated joint ventures	(13,894)	(11,736)
Distributions from unconsolidated joint ventures	10,213	6,825
Net proceeds from disposition of properties/land	351,301	134,024
Net proceeds from public reimbursement receivable/escrow	5,501	12,943
Investment in development in progress	(222,484)	(81,736)
Investment in land held for development	(73,547)	(34,642)
Investment in deferred leasing costs	(28,409)	(22,996)
Net cash used in investing activities	(130,476)	(199,155)
FINANCING ACTIVITIES
Redemption of preferred units	0	(64,500)
Proceeds from unsecured notes	0	448,646
Redemption of unsecured notes	(200,000)	0
Proceeds from mortgage loans	0	10,401
Repayments of mortgage loans	(9,329)	(3,977)
Proceeds from credit facility	179,750	344,050
Repayments on credit facility	(38,800)	(436,050)
Payment of deferred financing costs	(3,622)	(3,883)
Capital contributions	44,097	954,481
Distributions to partners	(215,471)	(178,589)
Net cash (used in) provided by financing activities	(243,375)	1,070,579
Net (decrease) increase in cash and cash equivalents	(123,520)	1,086,460
Decrease in cash and cash equivalents related to foreign currency translation	(808)	(246)
Cash and cash equivalents at beginning of period	163,414	38,356
Cash and cash equivalents at end of period	$ 39,086	$ 1,124,570