Goodwill and Other Intangible Assets (Tables)

9 Months Ended

Sep. 30, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Carrying amounts of goodwill by operating segments

The carrying amounts of goodwill by operating segments for the nine months ended September 30, 2017 were as follows:



	Community Banks		Insurance		Total
Balance at January 1, 2017	$	467,767	$	2,767	$	470,534
Addition to goodwill from acquisition	140,512		—		140,512
Adjustment to previously recorded goodwill	—		—		—
Balance at September 30, 2017	$	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
September 30, 2017
Core deposit intangibles	$	54,958	$	(29,911	)	$	25,047
Customer relationship intangible	1,970		(799		)	1,171
Total finite-lived intangible assets	$	56,928	$	(30,710	)	$	26,218
December 31, 2016
Core deposit intangibles	$	47,992	$	(25,188	)	$	22,804
Customer relationship intangible	1,970		(700		)	1,270
Total finite-lived intangible assets	$	49,962	$	(25,888	)	$	24,074

Current year amortization expense for finite-lived intangible assets

Current year amortization expense for finite-lived intangible assets was as follows for the periods presented.



	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2017		2016		2017		2016
Amortization expense for:
Core deposit intangibles	$	1,733	$	1,651	$	4,723	$	5,024
Customer relationship intangible	33		33		99		99
Total intangible amortization	$	1,766	$	1,684	$	4,822	$	5,123

Estimated amortization expense of finite-lived intangible assets

The estimated amortization expense of finite-lived intangible assets for the year ending December 31, 2017 and the succeeding four years is summarized as follows:



	Core Deposit Intangibles		Customer Relationship Intangible		Total

2017	$	6,399	$	131	$	6,530
2018	6,130		131		6,261
2019	5,212		131		5,343
2020	4,186		131		4,317
2021	3,107		131		3,238