Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2017

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment

Property, plant and equipment consists of the following:

December 31, (dollars in thousands)	2017		2016
Land	$	20,859	$	19,524
Buildings	107,659		102,666
Machinery and equipment	505,978		473,004
Furniture and fixtures	15,391		14,208
Software	24,464		22,733
Construction in progress	12,933		16,113
Gross property, plant and equipment	687,284		648,248
Less accumulated depreciation	421,609		391,856
Net property, plant and equipment	$	265,675	$	256,392