Business Segments and Geographic Information (Details 1) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Pre-Tax Income Reconciliation of Segments
Total operating income from segments	$ 65,957	$ 53,281	$ 125,124	$ 105,952
Unallocated Amount:
General and Administrative Expenses	(36,904)	(32,174)	(70,965)	(64,022)
Loss on extinguishment of debt	(15,866)	0	(15,866)	0
Income before income taxes and equity in earnings of affiliates	24,904	29,498	59,262	59,596
Operating Segments
Pre-Tax Income Reconciliation of Segments
Total operating income from segments	102,861	85,455	196,089	169,974
Segment Reconciling Items
Unallocated Amount:
General and Administrative Expenses	(36,904)	(32,174)	(70,965)	(64,022)
Net Interest Expense	$ (25,187)	$ (23,783)	$ (49,996)	$ (46,356)