Plant, Equipment and Timberlands (Tables)

12 Months Ended

Dec. 31, 2017

Property Plant And Equipment [Abstract]

Summary of Plant, Equipment and Timberlands

Plant, equipment and timberlands at December 31 were as follows:

In thousands		2017			2016
Land and buildings	$	221,436		$	192,877
Machinery and equipment		1,484,545			1,335,669
Furniture, fixtures, and other		174,462			142,110
Accumulated depreciation		(1,125,203	)		(1,036,825	)
		755,240			633,831
Construction in progress		105,673			137,665
Timberlands, less depletion		4,830			4,402
Total	$	865,743		$	775,898

Summary of Interest Expense Capitalized

The following table sets forth amounts of interest expense capitalized in connection with major capital projects:

	Year Ended December 31
	2017		2016		2015
Interest cost incurred	$	19,852	$	17,431	$	17,815
Interest capitalized		2,080		1,609		351
Interest expense	$	17,772	$	15,822	$	17,464