Geographical Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenue and long-lived assets by geographical segments
Revenues	$ 90,130	$ 93,818	$ 278,423	$ 283,003
United States
Revenue and long-lived assets by geographical segments
Revenues	65,146	69,984	201,053	208,042
North America (excluding U.S.)
Revenue and long-lived assets by geographical segments
Revenues	5,372	5,677	16,988	17,780
Europe, Middle East and Africa
Revenue and long-lived assets by geographical segments
Revenues	11,218	10,413	36,214	37,320
Asia Pacific
Revenue and long-lived assets by geographical segments
Revenues	6,407	5,241	19,483	15,039
Latin America
Revenue and long-lived assets by geographical segments
Revenues	$ 1,987	$ 2,503	$ 4,685	$ 4,822