CitiMortgage surprised few in the housing business on Monday when it announced that it agreed to a massive mortgage servicing rights deal with New Residential Investment and Nationstar Mortgage. As it often is with deals of this type, the devil is in the details. And one of the details of this deal is that the MSR sale is a precursor to CitiMortgage completely exiting the mortgage servicing business. Here’s a breakdown of how the deal works, and why Citi plans to leave mortgage servicing behind.