Intangibles

12 Months Ended

Dec. 31, 2012

Intangibles

Intangibles

(9)   Intangibles

        The Company's intangible lease assets were (in thousands):

	December 31,
Intangible lease assets	2012			2011
Lease-up intangibles	$	581,742		$	385,148
Above market tenant lease intangibles		153,141			145,374
Below market ground lease intangibles		58,939			41,015
Gross intangible lease assets		793,822			571,537
Accumulated depreciation and amortization		(241,121	)		(199,147	)
Net intangible lease assets	$	552,701		$	372,390

        The increase in intangible assets in 2012 from 2011 was primarily attributable to the acquisition of 129 senior housing communities from the Blackstone JV, comprised primarily of lease-up intangibles with an average amortization period of 15 years. The remaining weighted average amortization period of intangible assets was 12 years and 11 years at December 31, 2012 and 2011, respectively.

        The Company's intangible lease liabilities were (in thousands):

	December 31,
Intangible lease liabilities	2012			2011
Below market lease intangibles	$	192,733		$	206,460
Above market ground lease intangibles		6,091			1,779
Gross intangible lease liabilities		198,824			208,239
Accumulated depreciation and amortization		(92,915	)		(90,462	)
Net intangible lease liabilities	$	105,909		$	117,777

        The remaining weighted average amortization period of unfavorable market lease intangibles was approximately eight years at both December 31, 2012 and 2011.

        For the years ended December 31, 2012, 2011 and 2010, rental income includes additional revenues of $4.0 million, $6.2 million and $8.2 million, respectively, from the amortization of net below market lease intangibles. For the years ended December 31, 2012, 2011 and 2010, operating expenses include additional expense of $0.7 million, $0.6 million and $0.4 million, respectively, from the amortization of net above market ground lease intangibles. For the years ended December 31, 2012, 2011 and 2010, depreciation and amortization expense includes additional expense of $43.7 million, $44.8 million and $45.7 million, respectively, from the amortization of lease-up and non-compete agreement intangibles.

        Estimated aggregate amortization of intangible assets and liabilities for each of the five succeeding fiscal years and thereafter follows (in thousands):

	Intangible Assets		Intangible Liabilities
2013	$	72,684	$	16,772
2014		67,943		16,261
2015		64,078		15,696
2016		59,674		15,150
2017		52,452		12,787
Thereafter		235,870		29,243
	$	552,701	$	105,909