Segment Information (Details 1) (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
Reconciliation of consolidated net operating income
Consolidated net operating income									$ 339,441	$ 334,915	$ 319,345
Less:
Interest expense									(132,939)	(131,405)	(132,640)
Interest expense - amortization of deferred financing costs									(6,208)	(4,991)	(3,770)
Depreciation and amortization									(195,841)	(210,334)	(203,345)
Administrative expenses									(25,413)	(24,602)	(23,306)
Plus:
Interest income									3,012	1,813	3,218
Historic tax credit transaction income									11,840	12,026	0
Derivative Instruments, Gain (Loss) Recognized in Income, Net									(2,985)	0	0
Interest expense — financing obligation									(850)	0	0
Equity in income of real estate ventures									2,741	3,775	5,305
Net gain on sales of interests in real estate ventures									0	2,791	(22)
Net gain on sale of undepreciated real estate									0	45	0
Loss on real estate venture formation									(950)	(222)	0
Gain (loss) on early extinguishment of debt									(22,002)	(2,776)	(2,110)
Income (loss) from continuing operations									(30,154)	(18,965)	(37,325)
Income from discontinued operations									36,683	14,250	19,719
Net income (loss)	$ (26,698)	$ 17,089	$ 6,802	$ 9,336	$ (4,602)	$ 6,611	$ (6,234)	$ (490)	$ 6,529	$ (4,715)	$ (17,606)