Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Gains (Losses) on Extinguishment of Debt	$ (4,539)	$ 0
Net Income (Loss) Available to Common Stockholders, Diluted	35,254	15,371
Net Income Loss From Discontinuing Operation Available To Common Stockholders Diluted	562	(8,208)
Net Income Loss From Continuing Operation Available To Common Stockholders Diluted	34,692	23,579
Operating activities:
Net income	41,206	21,390
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Non-cash impairment charges	0	3,998
Loss (income) from discontinued operations	(562)	8,208
Equity in income from joint ventures	351	47
Distributions from joint ventures	223	354
Depreciation and amortization	13,438	11,740
Amortization of deferred financing costs	999	1,085
Share-based compensation expense to management and trustees	1,548	1,464
Decrease in restricted cash	2,946	1,450
Increase in mortgage notes and related accrued interest receivable	(36)	(13)
Decrease (increase) in accounts receivable, net	(1,426)	(232)
Increase in direct financing lease receivable	(1,212)	(1,256)
Decrease (increase) in other assets	139	(2,523)
Decrease in accounts payable and accrued liabilities	(10,451)	(6,768)
Increase (decrease) in unearned rents	(3,072)	2,628
Net operating cash provided by continuing operations	38,850	41,478
Net operating cash provided by discontinued operations	1,322	481
Net cash provided by operating activities	40,172	41,959
Investing activities:
Acquisition of rental properties and other assets	(8,174)	(31,507)
Investment in unconsolidated joint ventures	(433)	(442)
Investment in mortgage notes receivable	(12,769)	(24,451)
Additions to properties under development	(17,719)	(13,672)
Net cash used by investing activities of continuing operations	(39,095)	(70,072)
Net proceeds from sale of real estate from discontinued operations	24,146	282
Net cash provided (used) by investing activities	(14,949)	(69,790)
Financing activities:
Proceeds from long-term debt facilities	70,000	320,000
Principal payments on long-term debt	(48,950)	(251,328)
Deferred financing fees paid	(67)	(1,852)
Net proceeds from issuance of common shares	84	56
Impact of stock option exercises, net	(692)	(480)
Purchase of common shares for treasury	(3,245)	(3,209)
Dividends paid to shareholders	(41,146)	(38,681)
Net cash provided (used) by financing activities	(24,016)	24,506
Effect of exchange rate changes on cash	(108)	174
Net increase (decrease) in cash and cash equivalents	1,099	(3,151)
Cash and cash equivalents at beginning of the year	10,664	14,625
Cash and cash equivalents at end of the year	11,763	11,474
Supplemental schedule of non-cash activity:
Transfer of property under development to rental property	7,151	1,038
Issuance of nonvested shares and restricted share units at fair value, including nonvested shares issued for payment of bonuses	9,373	6,694
Conversion of equity to mortgage loan related to atlantic-EPR I	0	14,852
Supplemental disclosure of cash flow information:
Cash paid during the year for interest	29,352	21,845
Cash paid during the year for income taxes	$ 221	$ 197