Real Estate Intangibles

3 Months Ended

Mar. 31, 2014

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):


		March 31, 2014		December 31, 2013
Assets:
	In place lease intangibles	$	930,687	$	937,357
	Above market tenant leases		57,910		55,939
	Below market ground leases		59,165		59,165
	Lease commissions		18,864		18,293
	Gross historical cost		1,066,626		1,070,754
	Accumulated amortization		(649,362)		(571,008)
	Net book value	$	417,264	$	499,746

	Weighted-average amortization period in years		17.3		16.7

Liabilities:
	Below market tenant leases	$	76,340	$	76,381
	Above market ground leases		9,490		9,490
	Gross historical cost		85,830		85,871
	Accumulated amortization		(36,086)		(34,434)
	Net book value	$	49,744	$	51,437

	Weighted-average amortization period in years		14.3		14.3

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


	Three Months Ended
	March 31,
	2014		2013
Rental income related to above/below market tenant leases, net	$	(45)	$	148
Property operating expenses related to above/below market ground leases, net		(311)		(320)
Depreciation and amortization related to in place lease intangibles and lease commissions		(79,393)		(50,576)

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


		Assets		Liabilities
2014	$	131,571	$	3,319
2015		60,803		6,144
2016		27,796		5,230
2017		21,181		4,936
2018		18,396		4,609
Thereafter		157,517		25,506
Totals	$	417,264	$	49,744