Goodwill represents the excess of the consideration paid over the fair value of the net assets acquired or the excess of the fair value of the net liabilities assumed over the consideration received in a business combination. The 2019 acquisition of MidSouth resulted in goodwill of $63.4 million and the 2018 acquisition of the trust and asset management business resulted in goodwill of $46.6 million. The carrying amount of goodwill was $855.5 million and $791.0 million at December 31, 2019 and 2018, respectively. For additional information regarding changes to the Company’s carrying amount of goodwill, refer to Note 2 – Business Combinations.

The Company completed its annual impairment test of goodwill as of September 30, 2019 by performing a qualitative (“Step Zero”) assessment. The qualitative assessment involved the examination of changes in macroeconomic conditions, industry and market conditions, overall financial performance, cost factors and other relevant entity-specific events, including changes in management and other key personnel and changes in the share price of the Company’s common stock. As a result of the assessment, the Company concluded that its goodwill was not impaired.

Identifiable intangible assets with finite lives are amortized over the periods benefited and are evaluated for impairment similar to other long-lived assets. The purchase and carrying values of intangible assets subject to amortization at December 31, 2019 and 2018 were as follows:

	December 31, 2019
	Purchase		Accumulated		Carrying
(in thousands)	Value		Amortization		Value
Core deposit intangibles	$	247,455	$	168,577	$	78,878
Credit card and trust relationships		49,962		22,448		27,514
Merchant processing relationships		10,000		9,585		415
	$	307,417	$	200,610	$	106,807

	December 31, 2018
	Purchase		Accumulated		Carrying
(in thousands)	Value		Amortization		Value
Core deposit intangibles	$	215,955	$	151,446	$	64,509
Credit card and trust relationships		49,962		19,564		30,398
Merchant processing relationships		10,000		8,756		1,244
	$	275,917	$	179,766	$	96,151

Aggregate amortization expense by category of finite lived intangible assets for the years ended December 31, 2019, 2018 and 2017 is as follows:

	Years Ended December 31,
(in thousands)	2019		2018		2017
Core deposit intangibles	$	17,132	$	18,566	$	19,442
Credit card and trust relationships		2,883		2,682		1,975
Merchant processing relationships		829		802		1,000
	$	20,844	$	22,050	$	22,417

At December 31, 2019, the weighted-average remaining life of core deposit intangibles was approximately 10 years, and the weighted-average remaining life of other identifiable intangibles was approximately 15 years.

The following table shows estimated amortization expense of other intangible assets at December 31, 2019 for the five succeeding years and all years thereafter, calculated based on current amortization schedules.

(in thousands)
2020		$	19,916
2021			16,665
2022			14,033
2023			11,557
2024			9,413
Thereafter			35,223
	$		106,807