Goodwill and Other Intangible Assets (Tables)

3 Months Ended

Mar. 31, 2021

Goodwill and Intangible Assets Disclosure [Abstract]

Carrying amounts of goodwill by operating segments

The carrying amounts of goodwill by operating segments for the three months ended March 31, 2021 were as follows:

	Community Banks		Insurance		Total
Balance at January 1, 2021	$	936,916	$	2,767	$	939,683
Additions to goodwill and other adjustments	—		—		—
Balance at March 31, 2021	$	936,916	$	2,767	$	939,683

Summary of finite-lived intangible assets

The following table provides a summary of finite-lived intangible assets as of the dates presented:

	Gross Carrying Amount		Accumulated Amortization		Net Carrying Amount
March 31, 2021
Core deposit intangibles	$	82,492	$	(55,091)	$	27,401
Customer relationship intangible	2,470		(1,329)		1,141
Total finite-lived intangible assets	$	84,962	$	(56,420)	$	28,542
December 31, 2020
Core deposit intangibles	$	82,492	$	(53,539)	$	28,953
Customer relationship intangible	2,470		(1,284)		1,186
Total finite-lived intangible assets	$	84,962	$	(54,823)	$	30,139

Current year amortization expense for finite-lived intangible assets

Current year amortization expense for finite-lived intangible assets is presented in the table below.

	Three Months Ended
	March 31,
	2021		2020
Amortization expense for:
Core deposit intangibles	$	1,553	$	1,850
Customer relationship intangible	45		45
Total intangible amortization	$	1,598	$	1,895

Estimated amortization expense of finite-lived intangible assets

The estimated amortization expense of finite-lived intangible assets for the year ending December 31, 2021 and the succeeding four years is summarized as follows:

	Core Deposit Intangibles		Customer Relationship Intangible		Total
2021	$	5,860	$	181	$	6,041
2022	4,940		181		5,121
2023	4,044		181		4,225
2024	3,498		181		3,679
2025	3,103		181		3,284