Core Deposit Intangibles

9 Months Ended

Sep. 30, 2020

Goodwill and Intangible Assets Disclosure [Abstract]

Core Deposit Intangibles

CORE DEPOSIT INTANGIBLES

Core deposit intangibles are recorded on the acquisition date of an entity. During the one-year measurement period, the Corporation may record subsequent adjustments to these intangibles for provisional amounts recorded at the acquisition date. The MBT acquisition on September 1, 2019 resulted in a core deposit intangible of $16,527,000. Details regarding the MBT acquisition are discussed in NOTE 2. ACQUISITION of these Notes to Consolidated Condensed Financial Statements.

The carrying basis and accumulated amortization of recognized core deposit intangibles are noted below.

	September 30, 2020		December 31, 2019
Gross carrying amount	$	102,396	$	85,869
Core deposit intangibles acquired	—		16,527
Accumulated amortization	(71,945)		(67,434)
Total core deposit intangibles	$	30,451	$	34,962

The core deposit intangibles are being amortized primarily on an accelerated basis over their estimated useful lives, generally over a period of ten years. Intangible asset amortization expense for the three and nine months ended September 30, 2020 was $1,486,000 and $4,511,000, respectively, compared to $1,356,000 and $4,404,000, respectively, for the three and nine months ended September 30, 2019. Estimated future amortization expense is summarized as follows:

	Amortization Expense
2020	$	1,476
2021	5,429
2022	5,027
2023	4,827
2024	4,241
After 2024	9,451
	$	30,451