7. INTANGIBLE ASSETS

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


					September 30, 2018						December 31, 2017
					Gross		Accumulated		Net Book		Gross		Accumulated		Net Book
	Life				Amount		amortization		Value		Amount		amortization		Value
Customer lists	8	-	17	years	$	42,326	$	(14,623)	$	27,703	$	38,659	$	(12,721)	$	25,938
Trade name	10	-	12	years		6,168		(3,165)		3,003		6,213		(2,798)		3,415
Design and technologies	10	-	12	years		4,991		(2,637)		2,354		5,147		(2,443)		2,704
Patents			17	years		24		(9)		15		24		(8)		16
Total					$	53,509	$	(20,434)	$	33,075	$	50,043	$	(17,970)	$	32,073

Intangible assets resulting from the acquisition of the Maval OE Steering business were approximately $3,870 (Note 2). The intangible assets acquired consist of customer lists (the valuation and useful life of which have not been finalized).

Amortization expense for intangible assets was $872 and $813 for the quarters ended September 30, 2018 and 2017, respectively. For the nine months ended September 30, 2018 and 2017, amortization expense was $2,634 and $2,405, respectively.

Estimated future intangible asset amortization expense as of September 30, 2018 is as follows (in thousands):


	Estimated
	Amortization
	Expense
Remainder of 2018	$	883
2019		3,499
2020		3,499
2021		3,241
2022		3,241
2023		3,159
Thereafter		15,553
Total estimated amortization expense	$	33,075