7. INTANGIBLE ASSETS

Intangible assets on the Company’s condensed consolidated balance sheets consist of the following (in thousands):


					June 30, 2019						December 31, 2018
					Gross		Accumulated		Net Book		Gross		Accumulated		Net Book
	Life				Amount		amortization		Value		Amount		amortization		Value
Customer lists	8	-	17	years	$	64,400	$	(17,339)	$	47,061	$	64,439	$	(15,343)	$	49,096
Trade name	10	-	12	years		12,241		(3,712)		8,529		12,249		(3,305)		8,944
Design and technologies	10	-	12	years		12,993		(3,150)		9,843		13,023		(2,723)		10,300
Patents	17			years		24		(11)		13		24		(10)		14
Total					$	89,658	$	(24,212)	$	65,446	$	89,735	$	(21,381)	$	68,354

Intangible assets resulting from the acquisition of TCI were approximately $36,400 (Note 2). The intangible assets acquired consist of customer lists, a trade name and technology. The valuation and useful life of the purchased intangibles has not been finalized.

Intangible assets from the acquisition of the Maval OE Steering business were approximately $3,870 (Note 2). The intangible assets acquired consist of customer lists.

Amortization expense for intangible assets was $1,430 and $878 for the quarters ending June 30, 2019 and 2018, respectively. For the six months ended June 30, 2019 and 2018, amortization expense was $2,862 and $1,762, respectively.

Estimated future intangible asset amortization expense as of June 30, 2019 is as follows (in thousands):


	Estimated
	Amortization
	Expense
Remainder of 2019	$	2,865
2020		5,731
2021		5,478
2022		5,478
2023		5,397
2024		5,095
Thereafter		35,402
Total estimated amortization expense	$	65,446