Goodwill and Other Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2019

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:

	Years Ended December 31,
(dollars in thousands)	2019		2018			2017
Balance at beginning of period	$	1,036,258	$	828,051		$	655,018
Acquisitions and adjustments		736		208,787			173,033
Divestitures		—		(580	)		—
Balance at end of period	$	1,036,994	$	1,036,258		$	828,051

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, 2019 and 2018 were as follows:

	Gross		Accumulated			Net
	Carrying		Amortization			Carrying
(dollars in thousands)	Amount		and Impairment			Amount
December 31, 2019
Core deposit	$	119,051	$	(63,020	)	$	56,031
Customer trust relationships		16,547		(12,473	)		4,074
Total intangible assets	$	135,598	$	(75,493	)	$	60,105
December 31, 2018
Core deposit	$	129,100	$	(57,524	)	$	71,576
Customer trust relationships		16,547		(11,107	)		5,440
Total intangible assets	$	145,647	$	(68,631	)	$	77,016

Schedule of Estimated Amortization Expense for Future Years

Estimated amortization expense for future years is as follows:

(dollars in thousands)
2020	$	14,091
2021		11,336
2022		9,014
2023		7,053
2024		5,645
Thereafter		12,966
Total	$	60,105