Consolidated Statement Of Changes In Equity (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock [Member]	Preferred Stock [Member]	Additional paid-in capital [Member]	Treasury shares [Member]	Loans to shareholders [Member]	Accumulated other comprehensive income (loss) [Member]	Distributions in excess of net income [Member]	Noncontrolling Interests [Member]
Balance at Dec. 31, 2008	$ 1,292,651	$ 337	$ 167	$ 1,339,798	$ (26,357)	$ (1,925)	$ (6,169)	$ (28,417)	$ 15,217
Balance (in shares) at Dec. 31, 2008		33,734,181	16,650,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted share units issued to Trustees (in shares)		20,508	0
Restricted share units issued to Trustees	390	0	0	390	0	0	0	0	0
Issuance of nonvested shares, including nonvested shares issued for the payment of bonuses (in shares)		218,797	0
Issuance of nonvested shares, including nonvested shares issued for the payment of bonuses	2,415	2	0	2,413	0	0	0	0	0
Cancellation of employee nonvested shares	0			180	(180)	0	0	0	0
Amortization of nonvested shares	3,257			3,257	0	0	0	0	0
Share option expense	679			679	0	0	0	0	0
Foreign currency translation adjustment	34,325			0	0	0	34,325	0	0
Change in unrealized gain/loss on derivatives	(9,195)			0	0	0	(9,195)	0	0
Net income	(11,906)			0	0	0	0	8,007	(19,913)
Purchase of common shares for treasury	(1,201)			0	(1,201)	0	0	0	0
Issuances of common shares (in shares)		9,793,263	0
Issuances of common shares, net of costs	285,073	98	0	284,975	0	0	0	0	0
Stock option exercises, net (in shares)	100,928	100,928	0
Stock option exercises, net	(805)	1	0	1,424	(2,230)	0	0	0	0
Dividends to common and preferred shareholders	(127,517)			0	0	0	0	(127,517)	0
Distributions paid to noncontrolling interests	(209)		0	0	0	0	0	0	(209)
Balance at Dec. 31, 2009	1,467,957	438	167	1,633,116	(29,968)	(1,925)	18,961	(147,927)	(4,905)
Balance (in shares) at Dec. 31, 2009		43,867,677	16,650,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted share units issued to Trustees (in shares)		10,506	0
Restricted share units issued to Trustees	473	0	0	473	0	0	0	0	0
Issuance of nonvested shares, including nonvested shares issued for the payment of bonuses (in shares)		116,128	0
Issuance of nonvested shares, including nonvested shares issued for the payment of bonuses	1,296	1	0	1,295	0	0	0	0	0
Cancellation of employee nonvested shares	0			8	(8)	0	0	0	0
Amortization of nonvested shares	3,590			3,590	0	0	0	0	0
Share option expense	674			674	0	0	0	0	0
Foreign currency translation adjustment	19,070			0	0	0	19,070	0	0
Change in unrealized gain/loss on derivatives	(7,864)			0	0	0	(7,864)	0	0
Loss reclassified from accumulated other comprehensive income into earnings from termination of derivatives	8,675			0	0	0	8,675	0	0
Non-cash payment received on shareholder loans of 86,056 common shares	(1,617)			0	(3,261)	1,644	0	0	0
Payment received on shareholder loan	281			0	0	281	0	0	0
Net income	113,055			0	0	0	0	114,874	(1,819)
Purchase of common shares for treasury	(2,182)			0	(2,182)	0	0	0	0
Issuances of common shares (in shares)		3,606,368	0
Issuances of common shares, net of costs	141,242	36	0	141,206	0	0	0	0	0
Stock option exercises, net (in shares)	168,743	168,743	0
Stock option exercises, net	(815)	2	0	3,526	(4,343)	0	0	0	0
Dividends to common and preferred shareholders	(148,803)			0	0	0	0	(148,803)	0
Contributions from noncontrolling interests	10			0	0	0	0	0	10
Impact of litigation settlement including option granted on Concord land	36,216			1,483	0	0	0	0	34,733
Balance at Dec. 31, 2010	1,631,258	477	167	1,785,371	(39,762)	0	38,842	(181,856)	28,019
Balance (in shares) at Dec. 31, 2010		47,769,422	16,650,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted share units issued to Trustees (in shares)		10,519	0
Restricted share units issued to Trustees	502	0	0	502	0	0	0	0	0
Issuance of nonvested shares, including nonvested shares issued for the payment of bonuses (in shares)		137,020	0
Issuance of nonvested shares, including nonvested shares issued for the payment of bonuses	1,968	1	0	1,967	0	0	0	0	0
Amortization of nonvested shares	4,239			4,239	0	0	0	0	0
Share option expense	778			778	0	0	0	0	0
Foreign currency translation adjustment	1,651			0	0	0	1,651	0	0
Foreign currency translation gain reclassified from accumulated other comprehensive income into earnings from the substantial liquidation of foreign net assets	(23,236)			0	0	0	(23,236)	0	0
Change in unrealized gain/loss on derivatives	1,620			0	0	0	1,620	0	0
Loss reclassified from accumulated other comprehensive income into earnings from termination of derivatives	4,586			0	0	0	4,586	0	0
Net income	115,266			0	0	0	0	115,228	38
Purchase of common shares for treasury	(3,070)			0	(3,070)	0	0	0	0
Issuances of common shares (in shares)		10,436	0
Issuances of common shares, net of costs	472	1	0	471	0	0	0	0	0
Redemption of Series B preferred shares (in shares)		0	(3,200,000)
Redemption of Series B preferred shares	(80,030)	0	(32)	(77,229)	0	0	0	(2,769)	0
Stock option exercises, net (in shares)	135,196	135,196	0
Stock option exercises, net	966	1	0	2,967	(2,002)	0	0	0	0
Dividends to common and preferred shareholders	(158,864)			0	0	0	0	(158,864)	0
Purchase of subsidiary shares from noncontrolling interest	(3)								(3)
Balance at Dec. 31, 2011	$ 1,498,103	$ 480	$ 135	$ 1,719,066	$ (44,834)	$ 0	$ 23,463	$ (228,261)	$ 28,054
Balance (in shares) at Dec. 31, 2011		48,062,593	13,450,000