Goodwill and Other Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Changes in Carrying Amount of Goodwill

The following table shows the changes in the carrying amount of goodwill for the years ended December 31, 2017 and 2016:

	Years Ended December 31,
(dollars in thousands)	2017		2016
Balance at beginning of period	$	655,018	$	584,634
Acquisitions		173,033		111,347
Divestitures		—		(40,963	)
Balance at end of period	$	828,051	$	655,018

Schedule of Gross Carrying Amounts and Accumulated Amortization of Other Intangible Assets

The gross carrying amounts and accumulated amortization of other intangible assets at December 31, 2017 and 2016 was as follows:

(dollars in thousands)	Gross Carrying Amount		Accumulated Amortization and Impairment			Net Carrying Amount
December 31, 2017
Core deposit	$	108,923	$	(62,874	)	$	46,049
Customer trust relationships		16,547		(9,533	)		7,014
Customer loan relationships		4,413		(4,380	)		33
Total intangible assets	$	129,883	$	(76,787	)	$	53,096
December 31, 2016
Core deposit	$	81,663	$	(53,214	)	$	28,449
Customer trust relationships		16,547		(7,753	)		8,794
Customer loan relationships		4,413		(3,979	)		434
Total intangible assets	$	102,623	$	(64,946	)	$	37,677

Schedule of Estimated Amortization Expense for Future Years

Estimated amortization expense for future years is as follows:

(dollars in thousands)
2018	$	13,561
2019		11,115
2020		8,765
2021		6,498
2022		4,665
Thereafter		8,492
Total	$	53,096