Property, plant and equipment (Tables)

12 Months Ended

Dec. 31, 2019

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, 2019 and 2018 were as follows: 

	2019		2018
	(Dollars in thousands)
Land, buildings and leasehold improvements	$	248,067	$	224,605
Machinery and equipment	443,612		421,873
Computer equipment and software	158,574		137,899
Construction in progress	63,991		105,319
	914,244		889,696
Less: Accumulated depreciation	(483,525)		(456,930)
Property, plant and equipment, net	$	430,719	$	432,766

Schedule of Cash Flow, Supplemental Disclosures, Property, plant, and equipment

Supplemental cash flow information

	Year Ended December 31,
	2019		2018		2017
	(Dollars in thousands)
Non cash investing and financing activities of continuing operations:
Property, plant and equipment additions due to build-to-suit lease transactions	$	—	$	29,448	$	—