PROPERTY, PLANT & EQUIPMENT

12 Months Ended

Dec. 31, 2017

Property, Plant and Equipment [Abstract]

PROPERTY, PLANT & EQUIPMENT

PROPERTY, PLANT & EQUIPMENT

The major classes of depreciable assets are as follows:

	December 31,
In thousands	2017			2016
Machinery and equipment	$	728,257		$	645,354
Buildings and improvements	259,561			225,307
Land and improvements	38,228			41,569
Property, plant and equipment	1,026,046			912,230
Less: accumulated depreciation	(452,074		)	(393,854		)
Total	$	573,972		$	518,376

The estimated useful lives of property, plant and equipment are as follows:

	Years
Land improvements	10 to 20
Building and improvements	20 to 40
Machinery and equipment	3 to 15

Depreciation expense was $66.7 million, $47.1 million, and $43.1 million for 2017, 2016 and 2015, respectively.