Goodwill and intangible assets:

The following table summarizes changes in goodwill during the nine months ended September 30, 2019. There was no such activity during the nine months ended September 30, 2018.



	Goodwill
Balance at December 31, 2018	$	137,190
Addition from acquisition of Atlantic Capital branches (see Note 2)	31,396
Impairment due to sale of third party origination ("TPO") mortgage delivery channel	(100		)
Balance at September 30, 2019	$	168,486

Goodwill is tested annually, or more often if circumstances warrant, for impairment. If the implied fair value of goodwill is lower than its carrying amount, goodwill impairment is indicated and is written down to its implied fair value. Subsequent increases in goodwill values are not recognized in the financial statements. Goodwill impairment of $100 for the nine months ended September 30, 2019 is related to the goodwill assigned to the third party origination channel in the Mortgage segment, which was sold during the second quarter of 2019. There were no additions or impairment recorded during the nine months ended September 30, 2018.

Core deposit and other intangibles include core deposit intangibles, customer base trust intangible and manufactured housing servicing intangible. The change in core deposit and other intangibles during the three and nine months ended September 30, 2019 and 2018 is as follows:



	Core deposit and other intangibles
	Three Months Ended						Nine Months Ended
	September 30,						September 30,
	2019			2018			2019			2018
Beginning Balance	$	19,945		$	13,203		$	11,628		$	14,902
Addition of core deposit intangible from acquisition of Atlantic Capital branches (see Note 2)	—			—			10,760			—
Reclassification of leasehold intangible⁽¹⁾	—			—			(460		)	—
Less: amortization expense⁽²⁾	(1,197		)	(800		)	(3,180		)	(2,499		)
Ending Balance	$	18,748		$	12,403		$	18,748		$	12,403

(1) The Company adopted ASU 2016-02 "Leases" (Topic 842) on January 1, 2019 and reclassified $460 of leasehold intangibles to Operating lease right-of-use asset.

(2) The three and nine months ended September 30, 2018 includes $23 and $67, respectively, of amortization expense related to leasehold intangibles included in occupancy and equipment expense.

During the second quarter of 2019, the Company recorded $10,760 of core deposit intangibles resulting from the Atlantic Capital branch acquisition, which is being amortized over a weighted average life of approximately 6 years.

The estimated aggregate future amortization expense of the core deposit and other intangibles is as follows:



Remainder of 2019	$	1,159
December 31, 2020	4,262
December 31, 2021	3,663
December 31, 2022	2,973
December 31, 2023	2,247
Thereafter	4,444
	$	18,748