Segment Information (Details 4) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment Information
Long-lived assets	$ 266,849	$ 262,993	$ 234,549
United States
Segment Information
Long-lived assets	169,786	161,806	133,176
Belgium
Segment Information
Long-lived assets	64,567	66,077	64,051
China
Segment Information
Long-lived assets	16,990	17,864	19,319
United Kingdom
Segment Information
Long-lived assets	8,832	8,654	8,043
Japan
Segment Information
Long-lived assets	6,334	7,908	9,152
Canada
Segment Information
Long-lived assets	159	474	653
Singapore
Segment Information
Long-lived assets	77	106	135
Denmark
Segment Information
Long-lived assets	64	53
Brazil
Segment Information
Long-lived assets	28	36
Germany
Segment Information
Long-lived assets	$ 12	$ 15	$ 20