7. INTANGIBLE ASSETS

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


					September 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	$	64,151	$	(18,231)	$	45,920	$	64,439	$	(15,343)	$	49,096
Trade name	10	-	19	years		12,185		(3,899)		8,286		12,249		(3,305)		8,944
Design and technologies	10	-	15	years		12,802		(3,259)		9,543		13,023		(2,723)		10,300
Patents	17			years		24		(11)		13		24		(10)		14
Total					$	89,162	$	(25,400)	$	63,762	$	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 $1,429 and $872 for the quarters ending September 30, 2019 and 2018, respectively. For the nine months ended September 30, 2019 and 2018, amortization expense was $4,291 and $2,634, respectively.

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


	Estimated
	Amortization Expense
Remainder of 2019	$	1,424
2020		5,698
2021		5,454
2022		5,454
2023		5,374
2024		5,072
Thereafter		35,286
Total estimated amortization expense	$	63,762