Property, plant and equipment (Tables)

12 Months Ended

Dec. 31, 2014

Property, Plant and Equipment [Abstract]

Major Classes of Property, Plant and Equipment at Cost

The major classes of property, plant and equipment, at cost, at December 31, 2014 and 2013 are as follows:

	2014			2013
	(Dollars in thousands)
Land, buildings and leasehold improvements	$	194,923		$	199,741
Machinery and equipment	320,999			322,060
Computer equipment and software	107,743			102,527
Construction in progress	51,834			55,092
	675,499			679,420
Less: Accumulated depreciation	(358,064		)	(353,520		)
Property, plant and equipment, net	$	317,435		$	325,900