(6) Commitments

As of December 31, 2015, Forrester had future contractual obligations as follows for operating leases (in thousands):

2016	$	10,461
2017		10,655
2018		10,544
2019		10,343
2020		9,943
Thereafter		44,529
Total minimum lease payments	$	96,475

The cost of these operating leases, including any contractual rent increases, rent concessions, and landlord incentives, are recognized ratably over the life of the related lease agreement. Aggregate rent expense was $16.0 million, $15.9 million and $15.3 million for the years ended December 31, 2015, 2014, and 2013, respectively.