Investments in Real Estate and Real Estate Under Construction - Schedule of Net Real Estate (Details) - USD ($) $ in Thousands		Dec. 31, 2015	Dec. 31, 2014
Investments in Real Estate and Real Estate Under Construction [Line Items]
Buildings and building improvements		$ 3,032,457	$ 2,895,585
Land, land estates and land improvements		743,125	755,168
Fixtures and equipment		5,577	5,861
Construction in progress		8,552	14,946
Real estate - intangible assets		692,778	705,566
Investments in real estate under construction		95,402	106,238
Real estate, gross		4,577,891	4,483,364
Accumulated depreciation and amortization	[1]	(1,179,969)	(1,196,114)
Real estate, net		3,397,922	3,287,250
Accumulated amortization		367,762	400,628
Amortization expense, next 12 months		34,418
Amortization expense, year 2		30,561
Amortization expense, year 3		26,215
Amortization expense, year 4		20,943
Amortization expense, year 5		16,722
Leases, Acquired-in-Place [Member]
Investments in Real Estate and Real Estate Under Construction [Line Items]
Real estate - intangible assets		513,564	473,377
Tenant Relationships [Member]
Investments in Real Estate and Real Estate Under Construction [Line Items]
Real estate - intangible assets		123,796	133,796
Above Market Leases [Member]
Investments in Real Estate and Real Estate Under Construction [Line Items]
Real estate - intangible assets		$ 55,418	$ 98,393

[1] Includes accumulated amortization of real estate intangible assets of $367,762 and $400,628 in 2015 and 2014, respectively. The estimated amortization of the above real estate intangible assets for the next five years is $34,418 in 2016, $30,561 in 2017, $26,215 in 2018, $20,943 in 2019 and $16,722 in 2020.