Operating Segments and Geographic Information (Details 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Reconciliations of other segment measures to the consolidated totals
Total assets	$ 1,788,120	$ 1,696,484	$ 1,620,578
Total acquisition of property, plant and equipment	40,053	28,194	40,377
Operating Segments [Member]
Reconciliations of other segment measures to the consolidated totals
Total assets	1,459,651	1,328,705	1,236,200
Total acquisition of property, plant and equipment	29,570	24,363	31,756
Corporate Segment [Member]
Reconciliations of other segment measures to the consolidated totals
Total assets	328,469	367,779	251,049
Total acquisition of property, plant and equipment	10,483	3,655	8,110
Discontinued Operations [Member]
Reconciliations of other segment measures to the consolidated totals
Total assets	0	0	133,329
Total acquisition of property, plant and equipment		$ 176	$ 511