Accounts payable, accrued expenses, and tenant security deposits (Notes)

12 Months Ended

Dec. 31, 2019

Accounts payable, accrued expenses, and tenant security deposits

Accounts payable, accrued expenses, and other liabilities

The following table summarizes the components of accounts payable, accrued expenses, and other liabilities as of December 31, 2019 and 2018 (in thousands):



	December 31,
	2019		2018
Accounts payable and accrued expenses	$	198,994	$	215,539
Accrued construction	275,818		275,882
Acquired below-market leases	194,773		134,808
Conditional asset retirement obligations	14,037		10,343
Deferred rent liabilities⁽¹⁾	2,897		29,547
Interest rate hedge liabilities	—		768
Operating lease liability⁽¹⁾	271,808		—
Unearned rent and tenant security deposits	275,863		250,923
Other liabilities	86,078		63,897
Total	$	1,320,268	$	981,707


(1)	Refer to Note 2 – “Summary of Significant Accounting Policies” and Note 5 – “Leases” to our consolidated financial statements for additional information.

Some of our properties may contain asbestos, which, under certain conditions, requires remediation. Although we believe that the asbestos is appropriately contained in accordance with environmental regulations, our practice is to remediate the asbestos upon the development or redevelopment of the affected property. We recognize a liability for the fair value of a conditional asset retirement obligation (including asbestos) when the fair value of the liability can be reasonably estimated. For certain properties, we do not recognize an asset retirement obligation when there is an indeterminate settlement date for the obligation because the period in which we may remediate the obligation may not be estimated with any level of precision to provide a meaningful estimate of the retirement obligation.