Identified Intangible Assets and Liabilities

6 Months Ended

Jun. 30, 2016

Identified Intangible Assets and Liabilities [Abstract]

Identified Intangible Assets and Liabilities

9. 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 30,2016 and December 31,2015.

(Amounts in thousands)	Balance as of
	June 30, 2016		December 31, 2015
Identified intangible assets:
Gross amount	$	404,473	$	415,261
Accumulated amortization		(194,463)		(187,360)
Net	$	210,010	$	227,901
Identified intangible liabilities (included in deferred revenue):
Gross amount	$	600,722	$	643,488
Accumulated amortization		(311,197)		(325,340)
Net	$	289,525	$	318,148

Amortization of acquired below-market leases, net of acquired above-market leases, resulted in an increase to rental income of $12,301,000 and $13,378,000 for the three months ended June 30,2016 and 2015, respectively, and $29,808,000 and $25,828,000 for the six months endedJune 30,2016 and 2015, 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, 2017 is as follows:

(Amounts in thousands)
2017	$	45,361
2018		44,101
2019		31,937
2020		23,365
2021		18,287

Amortization of all other identified intangible assets (a component of depreciation and amortization expense) was $8,066,000 and $5,309,000 for the three months ended June 30,2016 and 2015, respectively, and $15,859,000 and $11,494,000 for the six months endedJune 30,2016 and 2015, 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, 2017 is as follows:

(Amounts in thousands)
2017	$	24,795
2018		20,541
2019		16,202
2020		12,404
2021		11,032

We are a tenant under ground leases for certain properties. Amortization of these acquired below-market leases, net of above-market leases, resulted in anincrease to rent expense of $458,000 and $458,000 for the three months ended June 30,2016 and 2015, respectively, and $916,000 and $916,000 for the six months endedJune 30,2016 and 2015. Estimated annual amortization of these below-market leases, net of above-market leases, for each of the five succeeding years commencing January 1, 2017 is as follows:

(Amounts in thousands)
2017	$	1,832
2018		1,832
2019		1,832
2020		1,832
2021		1,832