Goodwill and Other Intangible Assets

Goodwill

There were no changes in the carrying amount of goodwill during the three and nine months ended September 30, 2018 and 2017. Goodwill is reviewed annually for impairment and more frequently if potential impairment indicators exist. No impairment indicators were identified during the three and nine months ended September 30, 2018 and 2017. All of the Company's goodwill is associated with the Property and Casualty business segment (See Note 13. Segment Information for additional information on the reportable business segment).

Other Intangible Assets

The following table presents the components of other intangible assets:



	Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount		Useful Lives

	(Amounts in thousands)							(in years)
As of September 30, 2018:
Customer relationships	$	53,048	$	(46,798	)	$	6,250	11
Trade names	15,400		(6,256		)	9,144		24
Technology	4,300		(4,193		)	107		10
Insurance license	1,400		—			1,400		Indefinite
Total other intangible assets, net	$	74,148	$	(57,247	)	$	16,901

As of December 31, 2017:
Customer relationships	$	52,890	$	(43,617	)	$	9,273	11
Trade names	15,400		(5,775		)	9,625		24
Technology	4,300		(3,870		)	430		10
Insurance license	1,400		—			1,400		Indefinite
Total other intangible assets, net	$	73,990	$	(53,262	)	$	20,728

Other intangible assets are reviewed annually for impairment and more frequently if potential impairment indicators exist. No impairment indicators were identified during the three and nine months ended September 30, 2018 and 2017.

Other intangible assets with definite useful lives are amortized on a straight-line basis over their useful lives. Other intangible assets amortization expense was $1.4 million and $1.3 million for the three months ended September 30, 2018 and 2017, respectively, and $4.1 million and $4.0 million for the nine months ended September 30, 2018 and 2017, respectively.

The following table presents the estimated future amortization expense related to other intangible assets as of September 30, 2018:



Year	Amortization Expense
	(Amounts in thousands)
Remainder of 2018	$	1,367
2019	5,036
2020	889
2021	869
2022	845
Thereafter	6,495
Total	$	15,501