Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2013	Dec. 31, 2012
Accumulated amortization on deferred financing and leasing costs	$ 134,299,000	$ 132,261,000
Common shares, par value	$ 0.001	$ 0.001
Common shares, shares authorized	183,987,000	183,987,000
Common shares, shares issued	121,181,984	119,720,776
Common shares, shares outstanding	121,181,984	119,720,776
Treasury stock, shares	1,249,909	1,249,909
Noncontrolling Interest Operating Partnership Common Units Outstanding	3,713,851	3,713,851
Preferred stock, units outstanding	1,290,000	1,290,000
Liberty Property Limited Partnership [Member]
Accumulated amortization on deferred financing and leasing costs	$ 134,299,000	$ 132,261,000
Common shares, shares outstanding	119,932,075	118,470,867
Treasury stock, shares	1,249,909	1,249,909
Preferred stock, units outstanding	1,290,000	1,290,000
Limited Partners' Capital Account, Units Issued	3,713,851	3,713,851
Series I-2 [Member]
Preferred stock, units outstanding	301,483	301,483
Series I-2 [Member] | Liberty Property Limited Partnership [Member]
Preferred stock, units outstanding	301,483	301,483