Segment Reporting (Details 2) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Segment Reporting Asset Balances
Net investments in real estate	$ 3,325,933	$ 3,241,199
Goodwill	328,011	329,132
In Place Leases Net	465,931	447,278
Above Market Rent Net	269,355	279,885
Other Intangible Assets Net	12,256	10,200
Total Long-Lived Assets	4,379,506	4,306,251
Total Assets	4,635,360	4,609,042
Investment Management
Segment Reporting Asset Balances
Goodwill	63,607	63,607
Other Intangible Assets Net	6,130	5,651
Total Long-Lived Assets	69,737	69,258
Total Assets	260,550	124,221
Real Estate Ownership
Segment Reporting Asset Balances
Net investments in real estate	3,304,677	3,239,755
Goodwill	264,404	265,525
In Place Leases Net	465,931	447,278
Above Market Rent Net	269,355	279,885
Other Intangible Assets Net	5,403	4,550
Total Long-Lived Assets	4,309,769	4,236,993
Total Assets	$ 4,374,810	$ 4,484,821