Real Estate Intangibles

12 Months Ended

Dec. 31, 2020

Intangible Assets, Net (Excluding Goodwill) [Abstract]

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, 2020		December 31, 2019
Assets:
In place lease intangibles	$	1,406,705	$	1,513,836
Above market tenant leases	52,621		59,540
Lease commissions	40,704		43,675
Gross historical cost	1,500,030		1,617,051
Accumulated amortization	(1,177,513)		(1,181,158)
Net book value	$	322,517	$	435,893

Weighted-average amortization period in years	10.5		10.3

Liabilities:
Below market tenant leases	$	77,851	$	99,035


Accumulated amortization	(40,871)		(49,390)
Net book value	$	36,980	$	49,645

Weighted-average amortization period in years	8.3		8.6

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


	Year Ended December 31,
	2020		2019		2018
Rental income related to (above)/below market tenant leases, net	$	1,710	$	508	$	(1,269)
Amortization related to in place lease intangibles and lease commissions	(121,004)		(135,047)		(122,515)

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


	Assets		Liabilities
2021	$	78,160	$	7,993
2022	43,726		7,320
2023	34,071		5,158
2024	26,524		3,049
2025	21,324		2,482
Thereafter	118,712		10,978
Totals	$	322,517	$	36,980