Accounts Receivable (Tables)

12 Months Ended

Dec. 31, 2018

Receivables [Abstract]

Summary of Accounts Receivable

December 31,	2018			2017
(Dollars in thousands)
Trade receivables	$	101,864		$	152,476
Other receivables		7,083			10,016
		108,947			162,492
Allowance for doubtful accounts		(4,298	)		(2,325	)
Accounts receivable, net	$	104,649		$	160,167

Schedule of Revenues by Major Customers

	2018 Percent of Net Sales			2017 Percent of Net Sales			2016 Percent of Net Sales
Ford		18	%		22	%		38	%
GM		18	%		20	%		30	%
VW Group		12	%		9	%		<1	%
Toyota		8	%		9	%		14	%