Business Segments and Geographic Information (Details 1) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Pre-Tax Income Reconciliation of Segments
Total operating income from segments	$ 72,451	$ 63,031	$ 197,575	$ 168,977
Unallocated Amount:
General and Administrative Expenses	(37,483)	(33,742)	(108,448)	(97,764)
Loss on extinguishment of debt	0	0	(15,885)	0
Income before income taxes and equity in earnings of affiliates	46,951	38,709	106,213	98,300
Operating Segments
Pre-Tax Income Reconciliation of Segments
Total operating income from segments	109,934	96,773	306,023	266,741
Segment Reconciling Items
Unallocated Amount:
General and Administrative Expenses	(37,483)	(33,742)	(108,448)	(97,764)
Net Interest Expense	$ (25,500)	$ (24,322)	$ (75,477)	$ (70,677)