Segments Geographic Information (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
North America [Member]
Revenues From External Customers And Long Lived Assets Line Items
Revenues	$ 310,127	$ 268,519	$ 190,623
Long-Lived Assets	88,857	90,800	85,821
Europe [Member]
Revenues From External Customers And Long Lived Assets Line Items
Revenues	169,323	178,695	148,426
Long-Lived Assets	22,299	19,215	24,793
Asia/Pacific [Member]
Revenues From External Customers And Long Lived Assets Line Items
Revenues	157,062	151,468	125,189
Long-Lived Assets	19,720	15,225	14,099
South America [Member]
Revenues From External Customers And Long Lived Assets Line Items
Revenues	66,238	79,181	75,169
Long-Lived Assets	5,276	6,577	6,998
South Africa [Member]
Revenues From External Customers And Long Lived Assets Line Items
Revenues	5,476	5,368	4,656
Long-Lived Assets	21	28	41
Total [Member]
Revenues From External Customers And Long Lived Assets Line Items
Revenues	708,226	683,231	544,063
Long-Lived Assets	$ 136,173	$ 131,845	$ 131,752