Segment Reporting Schedule of Revenues from External Customers and Long-Lived Assets (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue, Net	$ 149,542	$ 143,483	$ 148,069	$ 153,647	$ 182,723	$ 197,265	$ 203,889	$ 213,643	$ 594,741	$ 797,520	$ 1,085,222
Property, Plant and Equipment, Net	129,882				143,211				129,882	143,211	149,014
Income Before Interest Expense and Taxes	21,524	$ 21,488	$ 20,227	$ 22,940	23,642	$ 46,818	$ 47,893	$ 42,717	86,179	161,070	346,531
Other Countries [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue, Net									347,331	414,805	464,335
Property, Plant and Equipment, Net	47,997				50,526				47,997	50,526	49,209
UNITED STATES
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue, Net									224,863	338,907	515,643
Property, Plant and Equipment, Net	71,388				80,603				71,388	80,603	83,748
CANADA
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue, Net									22,547	43,808	105,244
Property, Plant and Equipment, Net	$ 10,497				$ 12,082				$ 10,497	$ 12,082	$ 16,057