Property, Plant, and Equipment

3 Months Ended

Mar. 31, 2018

Property Plant And Equipment [Abstract]

9.	Property, Plant, and Equipment

The components of property, plant, and equipment were as follows (dollars in millions):

	March 31,			December 31,
	2018			2017
Land and land improvements	$	158.0		$	156.0
Buildings		734.4			729.8
Machinery and equipment		5,212.0			5,162.5
Construction in progress		239.0			194.5
Other		70.9			68.4
Property, plant and equipment, at cost		6,414.3			6,311.2
Less accumulated depreciation		(3,452.9	)		(3,386.3	)
Property, plant, and equipment, net	$	2,961.4		$	2,924.9

Depreciation expense for the three months ended March 31, 2018 and 2017 was $94.6 million and $82.4 million, respectively. During the three months ended March 31, 2018, we recognized $8.3 million incremental depreciation expense from shortening the useful lives of certain assets related to the Wallula mill restructuring and a corporate administration facility.

At March 31, 2018 and December 31, 2017, purchases of property, plant, and equipment included in accounts payable were $55.2 million and $29.8 million, respectively.