Goodwill and Other Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Rollforward of Goodwill

The following table shows a rollforward of goodwill by line of business:

(in thousands)	Community Banking		Wealth Manage- ment		Insurance			Consumer Finance		Total
Balance at January 1, 2016	$	812,399	$	8,020	$	10,858		$	1,809	$	833,086
Goodwill (deductions) additions	199,200		—		(157		)	—		199,043
Balance at December 31, 2016	1,011,599		8,020		10,701			1,809		1,032,129
Goodwill (deductions) additions	1,216,908		151		—			—		1,217,059
Balance at December 31, 2017	$	2,228,507	$	8,171	$	10,701		$	1,809	$	2,249,188

Summary of Core Deposit Intangibles, Customer Renewal Lists and Mortgage Servicing Rights

The following table shows a summary of core deposit intangibles and customer renewal lists:

(in thousands)	Core Deposit Intangibles			Customer Renewal Lists			Total
December 31, 2017
Gross carrying amount	$	195,582		$	12,442		$	208,024
Accumulated amortization	(106,938		)	(9,011		)	(115,949		)
Net carrying amount	$	88,644		$	3,431		$	92,075
December 31, 2016
Gross carrying amount	$	139,886		$	12,352		$	152,238
Accumulated amortization	(89,888		)	(8,544		)	(98,432		)
Net carrying amount	$	49,998		$	3,808		$	53,806

Schedule of Amortization Expense Recognized

The following table summarizes amortization expense recognized:

December 31	2017		2016		2015
(in thousands)
Amortization expense	$	17,517	$	11,210	$	8,305

Schedule of Expected Amortization Expenses on Finite-Lived Intangible Assets

Following is a summary of the expected amortization expense on finite-lived intangible assets, assuming no new additions, for each of the five years following December 31, 2017:

(in thousands)
2018	$	15,633
2019	13,532
2020	12,503
2021	11,339
2022	9,637
Total	$	62,644