Goodwill and Other Intangible Assets (Tables)

3 Months Ended

Mar. 31, 2018

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, 2018 were as follows:



	Community Banks		Insurance		Total
Balance at January 1, 2018	$	608,279	$	2,767	$	611,046
Addition to goodwill from acquisition	—		—		—
Adjustment to previously recorded goodwill	—		—		—
Balance at March 31, 2018	$	608,279	$	2,767	$	611,046

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, 2018
Core deposit intangibles	$	54,958	$	(33,204	)	$	21,754
Customer relationship intangible	1,970		(865		)	1,105
Total finite-lived intangible assets	$	56,928	$	(34,069	)	$	22,859
December 31, 2017
Core deposit intangibles	$	54,958	$	(31,586	)	$	23,372
Customer relationship intangible	1,970		(832		)	1,138
Total finite-lived intangible assets	$	56,928	$	(32,418	)	$	24,510

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,
	2018		2017
Amortization expense for:
Core deposit intangibles	$	1,618	$	1,530
Customer relationship intangible	33		33
Total intangible amortization	$	1,651	$	1,563

Estimated amortization expense of finite-lived intangible assets

The estimated amortization expense of finite-lived intangible assets for the year ending December 31, 2018 and the succeeding four years is summarized as follows:



	Core Deposit Intangibles		Customer Relationship Intangible		Total

2018	$	6,130	$	131	$	6,261
2019	5,212		131		5,343
2020	4,186		131		4,317
2021	3,107		131		3,238
2022	2,187		131		2,318