Business Segment, Geographic and Major Customer Information - Geographic Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 72,319	$ 87,030	$ 144,608	$ 169,404
U.S. [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	54,014	73,250	111,808	137,446
Other countries [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 18,305	$ 13,780	$ 32,800	$ 31,958