Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash Flows From Operating Activities
Net (loss) income	$ (24,368)	$ 5,593	$ (7,919)
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depreciation and amortization (including deferred financing costs, above/below market leases, debt premium/discount, leasehold interests, deferred rent receivable, note receivable closing costs and discount, and lease inducements)	114,575	104,045	72,678
Share-based compensation expense	17,408	3,221	1,313
Bad debt expense	1,064	1,447	1,022
Change in fair value of derivative financial instruments	7,667	856	(6,095)
Changes in operating assets and liabilities:
Accounts and other receivables	(1,323)	2,424	(7,102)
Other assets	(3,442)	(5,388)	(3,207)
Accounts payable and accrued liabilities	2,684	295	7,815
Accounts payable due to affiliates, net	0	0	(4,776)
Security deposits, prepaid rent and other liabilities	2,520	(686)	4,774
Net cash provided by operating activities	116,785	111,807	58,503
Cash Flows From Investing Activities
Acquisition of real estate operating properties	(257,386)	(61,385)	(597,097)
Capital expenditures	(22,909)	(16,034)	(14,888)
Restricted cash, escrow deposits and notes receivable	(4,830)	(4,502)	(12,614)
Release of restricted cash	580	14,463	0
Real estate deposits	0	0	(2,250)
Real estate deposits paid	(3,810)	(4,500)	0
Real estate deposits used	4,810	6,000	0
Net cash used in investing activities	(283,545)	(65,958)	(626,849)
Cash Flows From Financing Activities
Borrowings on secured real estate term loan and mortgage loans	0	125,500	79,125
Borrowings on unsecured revolving credit facility	360,000	0	7,000
Payments on unsecured revolving credit facility	(288,000)	(7,000)	0
Borrowings on unsecured term loans	455,000	0	0
Payments on fixed and variable rate mortgages	(128,601)	(192,083)	(123,117)
Deferred financing costs	(6,436)	(3,401)	(7,507)
Derivative financial instrument termination payments	0	0	(793)
Purchase of noncontrolling interest	0	0	(4,097)
Security deposits	765	596	2,144
Proceeds from issuance of common stock	0	214,641	594,677
Repurchase and cancellation of common stock, including the Tender Offer	(182,602)	(37,680)	(51,856)
Payment of offering costs	(2,884)	(21,137)	(56,621)
Distributions	(93,273)	(84,800)	(60,176)
Payment on earnout liability	(328)	0	0
Distributions to noncontrolling interest of limited partners	(416)	(264)	(164)
Net cash provided by (used in) financing activities	113,225	(5,628)	378,615
Net change in cash and cash equivalents	(53,535)	40,221	(189,731)
Cash and cash equivalents - beginning of period	69,491	29,270	219,001
Cash and cash equivalents - end of period	$ 15,956	$ 69,491	$ 29,270