Real Estate Intangibles

3 Months Ended

Jun. 30, 2012

Real Estate Intangibles [Abstract]

Real Estate Intangibles

4. Real Estate Intangibles

     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):

		June 30, 2012		December 31, 2011
Assets:
	In place lease intangibles	$	405,499	$	332,645
	Above market tenant leases		45,739		35,973
	Below market ground leases		58,604		51,316
	Lease commissions		14,303		8,265
	Gross historical cost		524,145		428,199
	Accumulated amortization		(206,832)		(148,380)
	Net book value	$	317,313	$	279,819
	Weighted-average amortization period in years		17.0		17.0
Liabilities:
	Below market tenant leases	$	72,384	$	67,284
	Above market ground leases		5,894		5,020
	Gross historical cost		78,278		72,304
	Accumulated amortization		(24,620)		(21,387)
	Net book value	$	53,658	$	50,917
	Weighted-average amortization period in years		12.6		12.3

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

	Three Months Ended June 30,				Six Months Ended June 30,
	2012		2011		2012		2011
Rental income related to above/below market tenant leases, net	$	282	$	874	$	887	$	1,592
Property operating expenses related to above/below market ground leases, net		(364)		(268)		(682)		(536)
Depreciation and amortization related to in place lease intangibles and lease commissions		(28,551)		(27,048)		(55,843)		(41,540)

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

		Assets		Liabilities
2012	$	67,938	$	3,450
2013		38,753		6,437
2014		25,899		5,979
2015		23,776		5,015
2016		25,016		4,657
Thereafter		135,931		28,120
Totals	$	317,313	$	53,658