offline/imported contributions annot update membership status

I'm looking at CiviCRM for managing membership records with yearly renewals. We'd expect to always receive a majority or renewals by postal mail.

Looking at the CiviContribute/CiviMember options, it does not seem that there is a way for imported or manually entered contributions to automatically trigger a membership renewal? That seems odd since the payment type of "Membership" is one of the defaults.

I guess this could be done by importing the transactions twice (once as a contribution, and again as a membership)?