Business Segments and Geographic Information (Details 1) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Pre-Tax Income Reconciliation of Segments
Total operating income from segments	$ 64,372	$ 59,167
Unallocated Amount:
General and Administrative Expenses	(42,586)	(34,061)
Income before income taxes and equity in earnings of affiliates	41,349	34,358
Operating Segments
Pre-Tax Income Reconciliation of Segments
Total operating income from segments	106,958	93,228
Segment Reconciling Items
Unallocated Amount:
General and Administrative Expenses	(42,586)	(34,061)
Net Interest Expense	$ (23,023)	$ (24,809)