CHFC 2018 Annual Report

Note 10: Other Intangible Assets The following table shows the net carrying value of the Corporation's other intangible assets. December 31, (Dollars in thousands) 2018 2017 Core deposit intangible assets $ 28,556 $ 34,259 Non-compete intangible assets — 12 Total other intangible assets $ 28,556 $ 34,271 Core Deposit Intangible Assets The Corporation recorded core deposit intangible assets associated with each of its acquisitions and its merger withTalmer. Core deposit intangible assets are amortized on an accelerated basis over their estimated useful lives and have an estimated remaining weighted-average useful life of 6.6 years as of December 31, 2018. The following table sets forth the carrying amount and accumulated amortization of core deposit intangible assets that are amortizable and arose from business combinations or other acquisitions: December 31, (Dollars in thousands) 2018 2017 Gross original amount $ 56,456 $ 59,143 Accumulated amortization 27,900 24,884 Net carrying amount $ 28,556 $ 34,259 Amortization expense recognized on core deposit intangible assets was $5.7 million, $6.0 million and $5.2 million for the years ended December 31, 2018, 2017 and 2016, respectively. The estimated future amortization expense on core deposit intangible assets for the next five years is as follows: (Dollars in thousands) Estimated amortization expense 2019 $ 5,441 2020 4,851 2021 4,471 2022 4,218 2023 3,591 Chemical Financial Corporation Notes to Consolidated Financial Statements December 31, 2018 136 Note 11: Derivative Instruments and Balance Sheet Offsetting In the normal course of business, the Corporation enters into various transactions involving derivative instruments to manage exposure to fluctuations in interest rates and to meet the financing needs of customers (customer-initiated derivatives). These financial instruments involve, to varying degrees, elements of market and credit risk. Market and credit risk are included in the determination of fair value. Commitments to fund mortgage loans (interest rate locks) to be sold into the secondary market and forward commitments for the future delivery of mortgage loans to third party investors are considered derivatives. It is the Corporation’s practice to enter into forward commitments for the future delivery of mortgage loans when interest rate lock commitments are entered into in order to economically hedge the effect of changes in interest rates resulting from its commitments to fund the loans. The Corporation enters into interest rate derivatives to provide a service to certain qualifying customers to help facilitate their respective risk management strategies. These customer-initiated derivatives are not used for interest rate risk management purposes and primarily consist of interest rate swaps, interest rate caps and floors and foreign exchange contracts. The Corporation