Condensed Consolidated Statements of Equity (Unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	Series H Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Distributions in Excess of Accumulated Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interest [Member]	Total
Balances at Dec. 31, 2011	$ 73,750	$ 3	$ 1,844,611	$ (408,066)	$ (72,771)	$ 116,201	$ 1,553,728
Balances (in shares) at Dec. 31, 2011	2,950,000	33,888,000
Comprehensive income (loss):
Net income	0	0	0	62,536	0	7,193	69,729
Changes in fair value of cash flow hedges and amortization of settlement swaps	0	0	0	0	648	42	690
Changes in fair value of marketable securities	0	0	0	0	(792)	(52)	(844)
Issuance of common stock under:
Stock option and restricted stock plans	0	0	2,240	0	0	0	2,240
Stock option and restricted stock plans shares (in shares)		42,000
Sale of common stock	0	0	170,944	0	0	0	170,944
Sale of common stock (in shares)		1,141,000
Equity based compensation costs	0	0	(350)	0	0	1,161	811
Contributions from Noncontrolling Interests	0		0	0	0	2,400	2,400
Distributions to noncontrolling interest	0	0	0	0	0	(9,134)	(9,134)
Redemptions of noncontrolling interest	0	0	0	0	0	(681)	(681)
Common and preferred stock dividends	0	0	0	(79,528)	0	0	(79,528)
Balances at Jun. 30, 2012	$ 73,750	$ 3	$ 2,017,445	$ (425,058)	$ (72,915)	$ 117,130	$ 1,710,355
Balances (in shares) at Jun. 30, 2012	2,950,000	35,071,000