Consolidated Statement of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement of Income and Comprehensive Income [Abstract]
Net earnings	$ 98,175	$ 107,062	$ 292,187	$ 283,139
Investment gains (losses):
Investment gains (losses) during the period	14,948	91,185	(232,481)	152,498
Income tax charge (benefit)	4,917	32,274	(82,526)	54,078
Investments gains (losses), net of tax	10,031	58,911	(149,955)	98,420
Less reclassification adjustments for:
Gains included in net earnings	17,922	832	31,115	7,491
Income tax charge	6,272	291	10,890	2,622
Gains included in net earnings, net of tax	11,650	541	20,225	4,869
Net unrealized investment gains (losses)	(1,619)	58,370	(170,180)	93,551
Foreign currency translation adjustment	5,410	(141)	4,265	(3,454)
Income tax benefit	(92)	(234)	(646)	(483)
Foreign currency translation adjustment, net of tax	5,502	93	4,911	(2,971)
Other comprehensive income (loss)	3,883	58,463	(165,269)	90,580
Comprehensive income (loss)	$ 102,058	$ 165,525	$ 126,918	$ 373,719