Segment Reporting (Schedule of Assets for the Reportable Segments) (Details) (USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010
Total assets	$ 2,936,348	$ 2,983,228
Owned and Managed [Member]
Total assets	2,633,916	2,698,509
Managed-Only [Member]
Total assets	116,509	127,960
Corporate and Other [Member]
Total assets	183,893	154,598
Discontinued Operations [Member]
Total assets	$ 2,030	$ 2,161