Identified Intangible Assets and Liabilities

6 Months Ended

Jun. 30, 2017

Identified Intangible Assets and Liabilities [Abstract]

Identified Intangible Assets and Liabilities

8. Identified Intangible Assets and Liabilities

The following summarizes our identified intangible assets (primarily above-market leases) and liabilities (primarily acquired below-market leases) as of June 30,2017 and December 31,2016.

(Amounts in thousands)	Balance as of
	June 30, 2017		December 31, 2016
Identified intangible assets:
Gross amount	$	387,791	$	400,061
Accumulated amortization		(211,285)		(207,330)
Total, net	$	176,506	$	192,731
Identified intangible liabilities (included in deferred revenue):
Gross amount	$	581,471	$	586,969
Accumulated amortization		(340,131)		(323,183)
Total, net	$	241,340	$	263,786

Amortization of acquired below-market leases, net of acquired above-market leases, resulted in an increase to rental income of $12,932,000 and $12,301,000 for the three months ended June 30,2017 and 2016, respectively, and $24,391,000 and $29,808,000 for the six months endedJune 30,2017 and 2016, respectively. Estimated annual amortization of acquired below-market leases, net of acquired above-market leases, for each of the five succeeding years commencing January 1, 2018 is as follows:

(Amounts in thousands)
2018	$	44,474
2019		32,297
2020		23,472
2021		18,646
2022		15,530

Amortization of all other identified intangible assets (a component of depreciation and amortization expense) was $6,971,000and $8,066,000for the three months ended June 30,2017 and 2016, respectively, and $14,079,000 and $15,859,000for the six months endedJune 30,2017 and 2016, respectively. Estimated annual amortization of all other identified intangible assets including acquired in-place leases, customer relationships, and third party contracts for each of the five succeeding years commencing January 1, 2018 is as follows:

(Amounts in thousands)
2018	$	20,073
2019		15,737
2020		12,291
2021		11,288
2022		9,532

We are a tenant under ground leases for certain properties. Amortization of these acquired below-market leases, net of above-market leases, resulted in an increase to rent expense (a component of operating expense) of $458,000 and $458,000 for the three months ended June 30,2017 and 2016, respectively, and $916,000 and $916,000 for the six months endedJune 30,2017 and 2016, respectively. Estimated annual amortization of these below-market leases, net of above-market leases, for each of the five succeeding years commencing January 1, 2018 is as follows:

(Amounts in thousands)
2018	$	1,832
2019		1,832
2020		1,832
2021		1,832
2022		1,832