Property, Plant and Equipment (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Cost	$ 769,542	$ 776,439
Accumulated depreciation	(433,872)	(415,442)
Total	335,670	360,997
Land
Property, Plant and Equipment [Line Items]
Cost	12,365	12,238
Buildings and improvements
Property, Plant and Equipment [Line Items]
Cost	104,615	85,815
Machinery, equipment and other
Property, Plant and Equipment [Line Items]
Cost	$ 652,562	$ 678,386