Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2017

Property, Plant and Equipment [Abstract]

Summary of Property, Plant and Equipment

Details of the Company's property, plant and equipment at December 31 are as follows:

	2017			2016
Land	$	87,878		$	84,404
Timber resources	41,664			41,441
Buildings	502,046			478,924
Machinery and equipment	2,871,622			2,637,753
Construction in progress	143,403			113,118
	3,646,613			3,355,640
Accumulated depreciation and depletion	(2,477,236		)	(2,295,623		)
Property, plant and equipment, net	$	1,169,377		$	1,060,017