Fee and Other Income (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Fee and Other Income [Abstract]
BMS cleaning fees	$ 61,754	$ 58,053	$ 53,824
Management and leasing fees	20,103	20,117	11,456
Lease termination fees	16,395	14,826	4,886
Other income	52,102	54,362	85,160
Total Fee and Other Income	$ 150,354	$ 147,358	$ 155,326