5.	Intangible Assets and Liabilities

The following summarizes our intangible assets (primarily acquired above-market leases and acquired in-place leases) and intangible liabilities (primarily acquired below-market leases) as of September 30, 2015 and December 31, 2014.

	As of
(Amounts in thousands)	September 30, 2015			December 31, 2014
Intangible assets:
Gross amount	$	663,367		$	689,894
Accumulated amortization		(116,935	)		(20,509	)
	$	546,432		$	669,385
Intangible liabilities:
Gross amount	$	222,772		$	222,985
Accumulated amortization		(29,730	)		(3,757	)
	$	193,042		$	219,228

Amortization of acquired below-market leases, net of acquired above-market leases, resulted in an increase to rental income of $1,477,000 and $3,239,000 for the three and nine months ended September 30, 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, 2016 is as follows.

(Amounts in thousands)
2016	$	20,130
2017		6,926
2018		8,832
2019		8,051
2020		6,677

Amortization of acquired in-place leases (a component of depreciation and amortization expense) was $29,376,000 and $100,006,000 for the three and nine months ended September 30, 2015, respectively. Estimated annual amortization of acquired in-place leases for each of the five succeeding years commencing January 1, 2016 is as follows.

(Amounts in thousands)
2016	$	87,347
2017		55,475
2018		49,128
2019		44,516
2020		39,002