Commitments and Contingencies:

12 Months Ended

Dec. 31, 2014

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies:

Commitments and Contingencies:

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 $10,968, $10,579 and $8,681 for the years ended December 31, 2014, 2013 and 2012, respectively. No contingent rent was incurred for the years ended December 31, 2014, 2013 or 2012.

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

Year Ending December 31,
2015	$	15,449
2016	15,472
2017	15,457
2018	11,342
2019	9,821
Thereafter	309,369
	$	376,910

As of December 31, 2014, the Company was contingently liable for $18,388 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, 2014, the Company had $41,205 in outstanding obligations, which it believes will be settled in the next twelve months.