NOTE 9. Intangibles

The following table summarizes the Company’s intangible lease assets (in thousands):


	December 31,
Intangible lease assets	2016		2015
Lease-up intangibles	$	719,788	$	765,861
Above market tenant lease intangibles		147,409		154,928
Below market ground lease intangibles		44,500		44,051
Gross intangible lease assets		911,697		964,840
Accumulated depreciation and amortization		(431,892)		(378,183)
Net intangible lease assets	$	479,805	$	586,657

The remaining weighted average amortization period of intangible lease assets was 13 years at both December 31, 2016 and 2015.

The following table summarizes the Company’s intangible lease liabilities (in thousands):


	December 31,
Intangible lease liabilities	2016		2015
Below market lease intangibles	$	161,595	$	149,762
Above market ground lease intangibles		2,329		6,121
Gross intangible lease liabilities		163,924		155,883
Accumulated depreciation and amortization		(105,779)		(99,736)
Net intangible lease liabilities	$	58,145	$	56,147

The remaining weighted average amortization period of intangible lease liabilities was 11 and 10 years at December 31, 2016 and 2015, respectively.

For the years ended December 31, 2016, 2015 and 2014, rental income includes additional revenues of $4 million, $4 million and $3 million, respectively, from the amortization of net below market lease intangibles. For the years ended December 31, 2016, 2015 and 2014, operating expenses include additional expense of $1 million each year from the amortization of net below market ground lease intangibles. For the years ended December 31, 2016, 2015 and 2014, depreciation and amortization expense includes additional expense of $85 million, $76 million and $60 million, respectively, from the amortization of lease-up and non-compete agreement intangibles.

The following table summarizes the estimated aggregate amortization of intangible assets and liabilities for each of the five succeeding fiscal years and thereafter (in thousands):


	Intangible		Intangible
	Assets		Liabilities
2017	$	86,113	$	11,686
2018		69,805		9,018
2019		51,710		6,558
2020		43,763		5,142
2021		37,255		3,636
Thereafter		191,159		22,105
	$	479,805	$	58,145