Business Segment, Geographic and Major Customer Information - Geographic Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 87,942	$ 116,761	$ 257,346	$ 324,653
U.S. [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	73,796	92,643	211,242	271,663
Other countries [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 14,146	$ 24,118	$ 46,104	$ 52,990