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 June 30, 2015 and December 31, 2014.

	As of
(Amounts in thousands)	June 30, 2015			December 31, 2014
Intangible assets:
Gross amount	$	686,284		$	689,894
Accumulated amortization		(103,158	)		(20,509	)
	$	583,126		$	669,385
Intangible liabilities:
Gross amount	$	222,903		$	222,985
Accumulated amortization		(21,064	)		(3,757	)
	$	201,839		$	219,228

Amortization of acquired below-market leases, net of acquired above-market leases, resulted in an increase to rental income of $872,000 and $1,762,000 for the three and six months ended June 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	$	10,159
2017		8,394
2018		10,299
2019		9,518
2020		8,231

Amortization of acquired in-place leases (a component of depreciation and amortization expense) was $37,638,000 and $70,630,000 for the three and six months ended June 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	$	79,941
2017		56,511
2018		50,164
2019		45,552
2020		40,525