Goodwill and Other Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2020

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of goodwill

The following table presents changes in the carrying value of goodwill for the periods indicated:

	2020		2019		2018
	(Dollars in thousands)
Balance, beginning of year	$	808,322	$	808,726	$	493,329
Goodwill acquired during the year	92,844		—		313,043
Purchase accounting adjustments	(2,597)		(404)		2,354
Balance, end of year	$	898,569	$	808,322	$	808,726
Accumulated impairment losses at end of year	$	—	$	—	$	—

Schedule of net intangible assets

The following table summarizes the change in the balance of core deposit intangibles and customer relationship intangible assets, and the related accumulated amortization for the periods indicated below:

	2020		2019		2018
	(Dollars in thousands)
Gross balance of intangible assets:
Balance, beginning of year	$	125,945	$	125,945	$	54,809
Additions due to acquisitions	19,267		—		71,136
Balance, end of year	145,212		125,945		125,945
Accumulated amortization:
Balance, beginning of year	(42,633)		(25,389)		(11,795)
Amortization	(17,072)		(17,244)		(13,594)
Balance, end of year	(59,705)		(42,633)		(25,389)
Net intangible assets, end of year	$	85,507	$	83,312	$	100,556