Real Estate Intangibles (Tables)

12 Months Ended

Dec. 31, 2011

Real Estate Intangibles (Tables) [Abstract]

Summary of real estate intangibles excluding those classified as held for sale

The following is a summary of our real estate intangibles, excluding those classified as held for sale, as of the dates indicated (dollars in thousands):

		December 31, 2011		December 31, 2010
Assets:
	In place lease intangibles	$	332,645	$	182,030
	Above market tenant leases		35,973		24,089
	Below market ground leases		51,316		46,992
	Lease commissions		8,265		4,968
	Gross historical cost		428,199		258,079
	Accumulated amortization		(148,380)		(49,145)
	Net book value	$	279,819	$	208,934
	Weighted-average amortization period in years		17.0		18.2
Liabilities:
	Below market tenant leases	$	67,284	$	57,261
	Above market ground leases		5,020		5,020
	Gross historical cost		72,304		62,281
	Accumulated amortization		(21,387)		(15,992)
	Net book value	$	50,917	$	46,289
	Weighted-average amortization period in years		12.3		14.0

The following is a summary of real estate intangible amortization for the periods presented (in thousands):

	Year Ended December 31,
	2011		2010		2009
Rental income related to above/below market tenant leases, net	$	3,340	$	3,829	$	2,670
Property operating expenses related to above/below market ground leases, net		(1,161)		(1,049)		(1,052)
Depreciation and amortization related to in place lease intangibles and lease commissions		(98,856)		(18,298)		(9,722)

The future estimated aggregate amortization of intangible assets and liabilities is as follows for the periods presented (in thousands):

		Assets		Liabilities
2012	$	85,656	$	6,108
2013		34,209		5,549
2014		17,136		5,169
2015		14,897		4,330
2016		17,801		4,129
Thereafter		110,120		25,632
Totals	$	279,819	$	50,917