Business Segment, Product, and Geographic Information Geographic Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Revenues and Net Property and Equipment by Geographical Areas [Line Items]
Total revenues	$ 190,677	$ 165,698	$ 368,172	$ 325,202
Property, Plant and Equipment, Net	134,863		134,863		128,064
UNITED STATES
Revenues and Net Property and Equipment by Geographical Areas [Line Items]
Total revenues	167,077	151,425	325,470	297,646
Property, Plant and Equipment, Net	110,625		110,625		109,458
International [Member]
Revenues and Net Property and Equipment by Geographical Areas [Line Items]
Total revenues	23,600	14,273	42,702	27,556
Property, Plant and Equipment, Net	$ 24,238		$ 24,238		$ 18,606