Segment Reporting (Reconciliation Of Segment Profit To Net Loss Attributable To Common Stockholders) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Segment Reporting [Abstract]
Total segments' profit									$ 388,602	$ 387,456	$ 393,362
General and administrative expenses									(27,943)	(29,286)	(28,305)
Depreciation and amortization									(184,849)	(205,696)	(225,030)
Other income									938	1,106	1,191
Loss, including depreciation, from unconsolidated real estate fund									(1,710)	(2,867)	(6,971)
Interest expense									(146,693)	(148,455)	(166,907)
Acquisition-related expenses									0	0	(296)
Net income (loss)	7,340	6,228	8,075	6,702	4,408	4,404	(6,209)	(345)	28,345	2,258	(32,956)
Less: Net (income) loss attributable to noncontrolling interests									(5,403)	(807)	6,533
Net income (loss) attributable to common stockholders	$ 5,974	$ 5,055	$ 6,527	$ 5,386	$ 3,419	$ 3,397	$ (5,016)	$ (349)	$ 22,942	$ 1,451	$ (26,423)