Discontinued Operations and Assets Held for Sale (Table Illustration of Discontinued Operations in Income Statement) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Discontinued Operations
Revenues	$ 184,571	$ 238,772	$ 264,240
Operating expenses	(85,120)	(103,818)	(110,185)
Depreciation and amortization	(55,229)	(80,578)	(94,670)
Operating income	44,222	54,376	59,385
Interest expense	(44,758)	(60,869)	(70,220)
Loss before impairment charges and gain on sales	(536)	(6,493)	(10,835)
Impairment charges	0	0	(27,206)
Gain on sale of depreciable properties	100,882	33,054	6,786
Income (loss) from discontinued operations	$ 100,346	$ 26,561	$ (31,255)