Commitments and Contingencies:

12 Months Ended

Dec. 31, 2015

Commitments and Contingencies Disclosure [Abstract]

The Company has certain properties subject to non-cancelable operating ground leases. The leases expire at various times through 2098, subject in some cases to options to extend the terms of the lease. Certain leases provide for contingent rent payments based on a percentage of base rental income, as defined in the lease. Ground lease rent expenses were $11,870, $10,968 and $10,579 for the years ended December 31, 2015, 2014 and 2013, respectively. No contingent rent was incurred for the years ended December 31, 2015, 2014 or 2013.

Minimum future rental payments required under the leases are as follows:



Year Ending December 31,
2016	$	15,695
2017	15,632
2018	11,249
2019	9,629
2020	9,637
Thereafter	283,154
	$	344,996

As of December 31, 2015, the Company was contingently liable for $62,788 in letters of credit guaranteeing performance by the Company of certain obligations relating to the Centers. The Company does not believe that these letters of credit will result in a liability to the Company.

The Company has entered into a number of construction agreements related to its redevelopment and development activities. Obligations under these agreements are contingent upon the completion of the services within the guidelines specified in the relevant agreement. At December 31, 2015, the Company had $32,006 in outstanding obligations, which it believes will be settled in the next twelve months.