Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2014

Finite-Lived Intangible Assets [Line Items]

Balances of major classes of depreciable assets and their respective estimated useful lives

Balances of major classes of depreciable assets (in thousands) and their respective estimated useful lives are:

		December 31,
Asset Category	Estimated Useful Life	2014		2013
Land	Non-depreciable	$	412,578	$	278,780
Buildings and garages	40 years	2,535,757		1,973,668
Building improvements	7 to 40 years	52,715		78,450
Tenant improvements	Lesser of useful life or term of lease	332,850		217,138
		$	3,333,900	$	2,548,036

Above and Below Market Leases

Finite-Lived Intangible Assets [Line Items]

Projected amortization expense for leases

As of December 31, 2014, the remaining amortization of net (above) and below market leases is projected as a net increase (decrease) to rental income as follows (in thousands):

	Amount
2015	$	14,343
2016	4,448
2017	3,052
2018	1,845
2019	2,844
Thereafter	(6,456		)
Total	$	20,076

Lease In Place Value

Finite-Lived Intangible Assets [Line Items]

Projected amortization expense for leases

As of December 31, 2014, the remaining amortization expense for the value of in-place leases is projected as follows (in thousands):

	Amount
2015	$	42,602
2016	26,390
2017	18,097
2018	11,880
2019	9,006
Thereafter	21,254
Total	$	129,229