Intangible Assets - Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Intangible Assets [Line Items]
Intangible Assets, Total Cost	$ 183,872	$ 169,224
Intangible Assets, Accumulated Amortization	(72,249)	(69,821)
Intangible Assets, net	111,623	99,403
Acquired Lease Intangibles, Gross	48,956	53,049
Acquired Lease Intangibles, Accumulated Amortization	(23,301)	(27,039)
Acquired Lease Intangibles, Net	25,655	26,010
Below market leases [Member]
Intangible Assets [Line Items]
Acquired Lease Intangibles, Gross	50,025
Acquired Lease Intangibles, Accumulated Amortization	(24,178)
Acquired Lease Intangibles, Net	25,847
Liabilities of assets held for sale [Member]
Intangible Assets [Line Items]
Acquired Lease Intangibles, Gross	1,069
Acquired Lease Intangibles, Accumulated Amortization	(877)
Acquired Lease Intangibles, Net	192
In-place lease value [Member]
Intangible Assets [Line Items]
Intangible Assets, Total Cost	161,276	129,411
Intangible Assets, Accumulated Amortization	(57,063)	(42,068)
Intangible Assets, net	104,213	87,343
Tenant relationship value [Member]
Intangible Assets [Line Items]
Intangible Assets, Total Cost	20,117	34,172
Intangible Assets, Accumulated Amortization	(15,580)	(26,344)
Intangible Assets, net	4,537	7,828
Above market leases acquired [Member]
Intangible Assets [Line Items]
Intangible Assets, Total Cost	5,333	5,641
Intangible Assets, Accumulated Amortization	(1,879)	(1,409)
Intangible Assets, net	3,454	$ 4,232
Intangible assets including assets held for sale [Member]
Intangible Assets [Line Items]
Intangible Assets, Total Cost	186,726
Intangible Assets, Accumulated Amortization	(74,522)
Intangible Assets, net	112,204
Assets held for sale [Member]
Intangible Assets [Line Items]
Intangible Assets, Total Cost	2,854
Intangible Assets, Accumulated Amortization	(2,273)
Intangible Assets, net	$ 581