Property, Plant and Equipment

12 Months Ended

Dec. 31, 2016

Property, Plant and Equipment [Abstract]

Property, plant and equipment consists of the following:



December 31, (dollars in thousands)	2016		2015
Land	$	19,524	$	19,871
Buildings	102,666		102,236
Machinery and equipment	473,004		470,862
Furniture and fixtures	14,208		14,313
Software	22,733		23,630
Construction in progress	16,113		9,137
Gross property, plant and equipment	648,248		640,049
Less accumulated depreciation	391,856		367,515
Net property, plant and equipment	$	256,392	$	272,534

Property, plant and equipment are stated at cost less accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of the assets, generally 3 to 14 years for equipment and furnishings and 10 to 40 years for buildings and improvements. Software consists of internally developed and purchased software packages for internal use. Capitalized costs include software packages, installation, and/or certain internal labor costs. These costs are generally amortized over a five-year period. Depreciation expense was $47.3 million, $41.4 million and $39.1 million for the years 2016, 2015 and 2014, respectively.