Fee and Other Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Fee and Other Income [Abstract]
BMS cleaning fees	$ 16,509	$ 16,982	$ 33,173	$ 32,492
Signage Revenue	8,347	4,879	14,828	9,469
Management and leasing fees	6,435	4,546	11,693	9,300
Lease termination fees	7,129	479	67,155	890
Other income	9,595	6,151	18,390	14,164
Fee and other income	48,015	33,037	145,239	66,315
Management fee income from Interstate Properties	131	192	333	391
Stop & Shop [Member]
Loss Contingencies [Line Items]
Litigation settlement date			2/6/2013
Proceed pursuant to a settlement agreement			124,000
Complaint regarding rent allocation	6,000		6,000
Accounts Receivable - collected upon settlement of litigation			47,900
Gain related to litigation settlement			$ 59,599