Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2019

Significant Accounting Policies [Abstract]

Detailed Information about Allowance for Doubtful Accounts

	2019		2018		2017
	(Dollars in thousands)
Allowance for doubtful accounts	$	1,756	$	1,343	$	2,490
Bad debt expense		808		511		35

Estimated Lives of Prperty, Plant and Equipment

Buildings	20 to 40 years
Machinery and equipment	5 to 15 years