Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2012

Significant Accounting Policies

Schedule of estimated useful lives

Category	Term
Building (fee ownership)	40 years
Building improvements	shorter of remaining life of the building or useful life
Building (leasehold interest)	lesser of 40 years or remaining term of the lease
Property under capital lease	remaining lease term
Furniture and fixtures	four to seven years
Tenant improvements	shorter of remaining term of the lease or useful life

Summary of identified intangible assets (acquired above-market leases and in-place leases) and intangible liabilities (acquired below-market leases)

The following summarizes our identified intangible assets (acquired above-market leases and in-place leases) and intangible liabilities (acquired below-market leases) as of December 31, 2012 and 2011 (amounts in thousands):

	December 31, 2012			December 31, 2011
Identified intangible assets (included in other assets):
Gross amount	$	725,861		$	673,495
Accumulated amortization		(263,107	)		(193,442	)
Net	$	462,754		$	480,053
Identified intangible liabilities (included in deferred revenue):
Gross amount	$	651,921		$	622,029
Accumulated amortization		(357,225	)		(290,893	)
Net	$	294,696		$	331,136

Schedule of estimated annual amortization of acquired below-market leases, net of acquired above-market leases

2013	$	(268	)
2014		390
2015		1,223
2016		3,415
2017		3,273

Schedule of estimated annual amortization of all other identifiable assets

2013	$	16,622
2014		12,887
2015		8,843
2016		5,556
2017		4,445

Schedule of marketable securities

At December 31, 2012 and 2011, we held the following marketable securities (amounts in thousands):

	December 31,
	2012		2011
Level 1—Equity marketable securities	$	2,202	$	8,065
Level 2—Commercial mortgage-backed securities		15,575		13,369
Level 3—Rake bonds		3,652		3,889
Total marketable securities available-for-sale	$	21,429	$	25,323