Goodwill and Other Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2020

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Changes in Carrying Amount of Goodwill

The following table presents the changes in the carrying amount of goodwill:

	Years Ended December 31,
(dollars in thousands)	2020		2019		2018
Balance at beginning of period	$	1,036,994	$	1,036,258	$	828,051
Acquisitions and adjustments	—		736		208,787
Divestitures	—		—		(580)
Balance at end of period	$	1,036,994	$	1,036,994	$	1,036,258

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

The gross carrying amounts and accumulated amortization of other intangible assets were as follows:

(dollars in thousands)	Gross Carrying Amount		Accumulated Amortization and Impairment		Net Carrying Amount
December 31, 2020
Core deposit	$	112,723	$	(69,623)	$	43,100
Customer trust relationships	16,547		(13,633)		2,914
Total intangible assets	$	129,270	$	(83,256)	$	46,014
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

Schedule of Estimated Amortization Expense for Future Years

Estimated amortization expense for future years is as follows:

(dollars in thousands)
2021	$	11,336
2022	9,014
2023	7,053
2024	5,645
2025	4,509
Thereafter	8,457
Total	$	46,014