Business Segment, Product, and Geographic Information Geographic Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Revenues and Net Property and Equipment by Geographical Areas [Line Items]
Total revenues	$ 177,496	$ 159,504
Property, Plant and Equipment, Net	128,857		128,064
UNITED STATES
Revenues and Net Property and Equipment by Geographical Areas [Line Items]
Total revenues	158,394	146,222
Property, Plant and Equipment, Net	108,924		109,458
International [Member]
Revenues and Net Property and Equipment by Geographical Areas [Line Items]
Total revenues	19,102	13,282
Property, Plant and Equipment, Net	$ 19,933		$ 18,606