The table below illustrates goodwill by segment for the years ended December 31, 2018 and 2017 ($ in thousands):

	General
	Banking		Insurance		Total
Balance as of January 1, 2017	$	321,132	$	45,024	$	366,156
Goodwill from Reliance merger during 2017		13,471		—		13,471
Balance as of December 31, 2017		334,603		45,024		379,627
Adjustment during 2018		—		—		—
Balance as of December 31, 2018	$	334,603	$	45,024	$	379,627

Trustmark’s General Banking Segment delivers a full range of banking services to consumer, corporate, small and middle-market businesses through its extensive branch network. During 2017, Trustmark recorded $13.5 million as goodwill from its merger with Reliance.

The Insurance Segment includes TNB’s wholly-owned retail insurance subsidiary that offers a diverse mix of insurance products and services. Trustmark performed goodwill impairment tests for the General Banking and Insurance Segments during 2018, 2017 and 2016. Based on these tests, Trustmark concluded that the fair value of both the General Banking and Insurance Segments substantially exceeded the book value and no impairment charge was required.

At December 31, 2018 and 2017, identifiable intangible assets consisted of the following ($ in thousands):

	December 31, 2018						December 31, 2017
	Gross Carrying		Accumulated		Net Carrying		Gross Carrying		Accumulated		Net Carrying
	Amount		Amortization		Amount		Amount		Amortization		Amount
Core deposit intangibles	$	87,674	$	78,353	$	9,321	$	87,674	$	73,494	$	14,180
Insurance intangibles		13,824		12,348		1,476		13,824		12,026		1,798
Banking charters		1,325		1,010		315		1,325		943		382
Borrower relationship intangible		—		—		—		690		690		—
Total	$	102,823	$	91,711	$	11,112	$	103,513	$	87,153	$	16,360

Trustmark recorded $5.2 million of amortization of identifiable intangible assets in 2018, $6.2 million in 2017 and $6.9 million in 2016. Trustmark estimates that amortization expense for identifiable intangible assets will be $4.0 million in 2019, $2.7 million in 2020, $1.9 million in 2021, $1.1 million in 2022 and $427 thousand in 2023. Trustmark continually evaluates whether events and circumstances have occurred that indicate that identifiable intangible assets have become impaired. Measurement of any impairment of such identifiable intangible assets is based on the fair values of those assets. There were no impairment losses on identifiable intangible assets recorded during 2018, 2017 or 2016.

The following table illustrates the carrying amounts and remaining weighted-average amortization periods of identifiable intangible assets as of December 31, 2018 ($ in thousands):

			Remaining
			Weighted-
			Average
	Net Carrying		Amortization
	Amount		Period in Years
Core deposit intangibles	$	9,321		4.4
Insurance intangibles		1,476		15.5
Banking charters		315		4.7
Total	$	11,112		5.9