Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Cash flows from operating activities
Net earnings	$ 125,420	$ 204,641
Adjustments to reconcile net earnings to net cash provided by (used in) operating activities:
Depreciation and amortization	42,083	34,406
Net realized capital (gains) losses	(43,151)	(96,836)
Other than temporary impairment losses	52,281	5,220
(Increase) decrease in reinsurance recoverables, net of reinsurance payable	215	26,318
(Increase) decrease in premium balances receivable	44,282	(113,005)
(Increase) decrease in ceded unearned premiums	(12,756)	(12,011)
(Increase) decrease in deferred acquisition costs	(16,662)	(23,658)
Increase (decrease) in unearned premiums	68,644	92,398
Increase (decrease) in loss and loss adjustment expenses	(182,881)	(87,822)
Change in unrealized foreign exchange losses (gains)	154,741	(18,543)
Other, net	(14,895)	(126,845)
Net adjustments	91,901	(320,378)
Net cash provided by (used in) operating activities	217,321	(115,737)
Cash flows from investing activities
Purchases of debt securities	(2,122,464)	(1,744,739)
Purchases of equity securities	(1,385,109)	(704,290)
Sales of debt securities	1,596,406	1,668,560
Maturities and redemptions of debt securities	353,149	244,451
Sales of equity securities	1,132,816	314,160
Net (purchase) sale in short-term investments	230,725	418,649
Purchases of property and equipment	(10,609)	(12,019)
Purchase of subsidiary, net of cash acquired	(43,900)
Other, net	1,232	(1,499)
Net cash (used in) provided by investing activities	(247,754)	183,273
Cash flows from financing activities
Treasury stock acquisitions	(26,632)	(94,642)
Other, net	7,344	8,929
Net cash (used in) provided by financing activities	(19,288)	(85,713)
Effect of exchange rate changes on cash	(18,053)	1,276
Net (decrease) increase in cash	(67,774)	(16,901)
Cash at beginning of period	605,259	498,315
Cash at end of period	537,485	481,414
Cash paid during the period for:
Interest paid	16,406	8,580
Income taxes paid (refunds received)	$ (1,787)	$ 71,106