Income Taxes (Effective Tax Rate Reconciliation) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Differences between our effective tax rate for financial statement purposes and the Federal statutory rate
Statutory tax rate	35.00%	35.00%	35.00%	35.00%
Federal tax at statutory rate	$ 40,095	$ 48,175	$ 92,885	$ 102,415
Nontaxable municipal bond interest and dividend received deduction	(6,889)	(8,856)	(16,641)	(17,783)
State income taxes, net of federal tax benefit	722	816	1,439	1,650
Foreign income taxes	6,011	8,640	15,962	15,866
Foreign tax credits	(5,852)	(8,640)	(15,628)	(15,866)
Indefinitely reinvested earnings of foreign subsidiaries			(9,134)
Uncertain tax positions (net of federal tax benefit on state positions: $71 in 2015, $183 in 2014)	(56)	132	2,178	452
Other, net	109	241	990	835
Income tax expense	$ 34,140	$ 40,508	$ 72,051	$ 87,569
Effective tax rate	29.80%	29.40%	27.10%	29.90%