Supplemental Information (Supplemental Cash Flow Information) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Supplemental Information
Income taxes paid	$ 57,259	$ 70,891	$ 86,185	$ 70,413
Interest paid	11,861	13,445	14,022	14,984
Proceeds from sales of available for sale fixed maturity securities	231,642	167,832	398,848	286,843
Proceeds from sales of equity securities	5,558	26,107	71,970	170,182
Dividends declared but not paid at end of period	$ 28,172	$ 22,493	$ 28,172	$ 22,493