Shareholders' Equity - Common Shares (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2014 USD ($) $ / shares shares	Dec. 31, 2013 USD ($) $ / shares shares
Continuous Equity Offering [Abstract]
Common stock, Continuous equity offering program, Max amount of equity	$ 200,000
Proceeds from Issuance of Common Stock	38,797	$ 58,473	$ 969,468
Common units [Member]
Common Shares [Abstract]
Dividends, Common Stock, Cash	$ 289,300	$ 286,900	$ 247,400
Common Stock, Ordinary Dividend, Per Share, Cash Paid | $ / shares	$ 1.4348	$ 1.2556	$ 1.4312
Common Stock, Capital gain 20%, Per Share, Cash Paid | $ / shares	0.1112	0.0000	0.0016
Common Stock, IRC SEC 1250 unrecaptured gain 25%, Per Share, Cash Paid | $ / shares	0.3372	0.3712	0.4672
Common Stock, Return of Capital, Per Share, Cash Paid | $ / shares	0.0168	0.2732	0.0000
Common Stock, Dividends, Per Share, Cash Paid | $ / shares	$ 1.9000	$ 1.9000	$ 1.9000
Common shares [Member]
Common Units [Abstract]
Units issued as a result of acquisitions | shares	0	0	0
Dividend Reinvestment and Share Purchase Plan [Abstract]
Stock Issued During Period, Shares, Dividend Reinvestment Plan | shares	1,036,437	1,643,536	1,248,842
Continuous Equity Offering [Abstract]
Number of common shares issued | shares	0	0	1,900,000
Proceeds from Issuance of Common Stock			$ 75,000
Share Repurchase [Abstract]
Share repurchase, shares | shares	2,321,794	0	0
2015 Share Repurchase Program [Member] | Common shares [Member]
Share Repurchase [Abstract]
Stock Repurchase Program, Authorized Amount	$ 250,000
Share repurchase, shares | shares	2,300,000
Share repurchase, value	$ 71,800
Liberty Property Limited Partnership [Member]
Common Units [Abstract]
Common units outstanding | shares	3,539,075	3,556,566
Redeemable Noncontrolling Interest, Equity, Common, Fair Value	$ 109,900
Liberty Property Limited Partnership [Member] | Common units [Member]
Common Units [Abstract]
Units issued as a result of acquisitions | shares	0	0	0
Dividend Reinvestment and Share Purchase Plan [Abstract]
Stock Issued During Period, Shares, Dividend Reinvestment Plan | shares	1,036,437	1,643,536	1,248,842
Continuous Equity Offering [Abstract]
Common stock, Continuous equity offering program, Max amount of equity	$ 200,000
Number of common shares issued | shares	0	0	1,900,000
Proceeds from Issuance of Common Stock			$ 75,000
Liberty Property Limited Partnership [Member] | 2015 Share Repurchase Program [Member] | Common units [Member]
Share Repurchase [Abstract]
Stock Repurchase Program, Authorized Amount	$ 250,000
Share repurchase, shares | shares	2,300,000
Share repurchase, value	$ 71,800
Conversion Ratio of Common Units to Common Shares [Member]
Common Units [Abstract]
Common Unit, Convertible to Common Stock	1
Common Stock, Converted from Common Unit	1