Property, Plant and Equipment

6 Months Ended

Jun. 30, 2015

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment

Property, Plant and Equipment

The components of property, plant and equipment are as follows:

(in thousands)	June 30, 2015		December 31, 2014		June 30, 2014
Land	$	29,902	$	23,380	$	22,055
Land improvements and leasehold improvements	75,822		71,817		68,003
Buildings and storage facilities	296,035		275,059		234,745
Machinery and equipment	356,759		333,559		314,427
Software	68,456		55,436		55,710
Construction in progress	21,803		29,620		18,362
	848,777		788,871		713,302
Less: accumulated depreciation and amortization	359,632		335,264		322,715
	$	489,145	$	453,607	$	390,587

Depreciation and amortization expense on property, plant and equipment amounted to $25.4 million and $20.4 million for the six months ended June 30, 2015 and 2014, respectively. Depreciation and amortization expense on property, plant and equipment were $13.0 million and $10.6 million for the three months ended June 30, 2015 and 2014, respectively.

Rail Group Assets

The components of Rail Group assets leased to others are as follows:

(in thousands)	June 30, 2015		December 31, 2014		June 30, 2014
Rail Group assets leased to others	$	422,810	$	384,958	$	323,881
Less: accumulated depreciation	91,978		87,211		81,734
	$	330,832	$	297,747	$	242,147

Depreciation expense on Rail Group assets leased to others amounted to $8.3 million and $6.9 million for the six months ended June 30, 2015 and 2014, respectively. Depreciation expense on Rail Group assets leased to others amounted to $4.3 million and $3.5 million for the three months ended June 30, 2015 and 2014, respectively.

Amortization expense on intangible assets was $2.1 million and $3.4 million for the three and six months ended June 30, 2015, and $1.6 million and $3.0 million for the three and six months ended June 30, 2014.