Goodwill and Other Intangible Assets (Tables)

3 Months Ended

Mar. 31, 2021

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of goodwill

	March 31,		March 31,
	2021		2020
	(Dollars in thousands)
Balance, beginning of year	$	898,569	$	808,322
Purchase accounting adjustments	1,635		—
Balance, end of year	$	900,204	$	808,322
Accumulated impairment losses at end of year	$	—	$	—

Schedule of finite-lived intangible assets

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

	Three Months Ended
	March 31,		December 31,		March 31,
	2021		2020		2020
	(Dollars in thousands)
Gross amount of intangible assets:
Beginning balance	$	145,212	$	145,212	$	125,945
Additions due to acquisitions	—		—		—
Ending balance	145,212		145,212		125,945
Accumulated amortization:
Beginning balance	(59,705)		(55,200)		(42,633)
Amortization	(4,143)		(4,505)		(3,963)
Ending balance	(63,848)		(59,705)		(46,596)
Net intangible assets	$	81,364	$	85,507	$	79,349