Guarantor and Non-Guarantor Financial Information - Condensed Consolidated Statements of Cash Flows (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	$ 70,053	$ 42,025
Cash Flows from Investing Activities:
Investment in real estate assets and real estate related intangibles, net of accruals	(27,587)	(281,613)
Net sales proceeds from wholly-owned properties	22,322	3,403
Investments in unconsolidated joint ventures	0	(672)
Deferred lease costs paid	(4,180)	(7,897)
Net cash used in investing activities	(9,445)	(286,779)
Cash Flows from Financing Activities:
Deferred financing costs paid	(454)	(47)
Proceeds from debt	764,564	294,000
Repayments of debt	(737,000)	(11,000)
Repurchases of common stock as part of announced plan	(54,515)	(11)
(Distributions to)/repayments from affiliates	0	0
Dividends paid and discount on dividend reinvestments	(30,905)	(33,570)
Net cash (used in)/provided by financing activities	(58,310)	249,372
Net increase in cash and cash equivalents	2,298	4,618
Cash and cash equivalents, beginning of period	6,973	12,957
Cash and cash equivalents, end of period	9,271	17,575
Issuer [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	21,395	4,103
Cash Flows from Investing Activities:
Investment in real estate assets and real estate related intangibles, net of accruals	(6,875)	(2,534)
Net sales proceeds from wholly-owned properties	22,322	3,403
Investments in unconsolidated joint ventures		(672)
Deferred lease costs paid	(720)	(2,218)
Net cash used in investing activities	14,727	(2,021)
Cash Flows from Financing Activities:
Deferred financing costs paid	(454)	(47)
Proceeds from debt	764,564	294,000
Repayments of debt	(162,000)	(11,000)
Repurchases of common stock as part of announced plan	0	0
(Distributions to)/repayments from affiliates	(635,349)	(279,021)
Dividends paid and discount on dividend reinvestments	0	0
Net cash (used in)/provided by financing activities	(33,239)	3,932
Net increase in cash and cash equivalents	2,883	6,014
Cash and cash equivalents, beginning of period	3,352	62,371
Cash and cash equivalents, end of period	6,235	68,385
Guarantor [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	594	177
Cash Flows from Investing Activities:
Investment in real estate assets and real estate related intangibles, net of accruals	0	0
Net sales proceeds from wholly-owned properties	0	0
Investments in unconsolidated joint ventures		0
Deferred lease costs paid	0	0
Net cash used in investing activities	0	0
Cash Flows from Financing Activities:
Deferred financing costs paid	0	0
Proceeds from debt	0	0
Repayments of debt	0	0
Repurchases of common stock as part of announced plan	(54,515)	(11)
(Distributions to)/repayments from affiliates	84,826	33,315
Dividends paid and discount on dividend reinvestments	(30,905)	(33,570)
Net cash (used in)/provided by financing activities	(594)	(266)
Net increase in cash and cash equivalents	0	(89)
Cash and cash equivalents, beginning of period	150	239
Cash and cash equivalents, end of period	150	150
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	41,908	32,198
Cash Flows from Investing Activities:
Investment in real estate assets and real estate related intangibles, net of accruals	(20,712)	(279,079)
Net sales proceeds from wholly-owned properties	0	0
Investments in unconsolidated joint ventures		0
Deferred lease costs paid	(3,460)	(5,679)
Net cash used in investing activities	(24,172)	(284,758)
Cash Flows from Financing Activities:
Deferred financing costs paid	0	0
Proceeds from debt	0	0
Repayments of debt	(575,000)	0
Repurchases of common stock as part of announced plan	0	0
(Distributions to)/repayments from affiliates	556,679	251,253
Dividends paid and discount on dividend reinvestments	0	0
Net cash (used in)/provided by financing activities	(18,321)	251,253
Net increase in cash and cash equivalents	(585)	(1,307)
Cash and cash equivalents, beginning of period	3,471	(49,653)
Cash and cash equivalents, end of period	2,886	(50,960)
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	6,156	5,547
Cash Flows from Investing Activities:
Investment in real estate assets and real estate related intangibles, net of accruals	0	0
Net sales proceeds from wholly-owned properties	0	0
Investments in unconsolidated joint ventures		0
Deferred lease costs paid	0	0
Net cash used in investing activities	0	0
Cash Flows from Financing Activities:
Deferred financing costs paid	0	0
Proceeds from debt	0	0
Repayments of debt	0	0
Repurchases of common stock as part of announced plan	0	0
(Distributions to)/repayments from affiliates	(6,156)	(5,547)
Dividends paid and discount on dividend reinvestments	0	0
Net cash (used in)/provided by financing activities	(6,156)	(5,547)
Net increase in cash and cash equivalents	0	0
Cash and cash equivalents, beginning of period	0	0
Cash and cash equivalents, end of period	$ 0	$ 0