Investments (Details 5) (USD $) In Thousands, unless otherwise specified	3 Months Ended			6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012	Jun. 30, 2013		Jun. 30, 2012
Reconciliation of net unrealized investment gains (losses) on fixed maturity securities and equity securities
Reclassification of net realized investment (gains) losses to net income	$ 10,021	[1],[2]		$ 14,481	[1],[2]
Fixed Maturity Securities [Member]
Reconciliation of net unrealized investment gains (losses) on fixed maturity securities and equity securities
Beginning of period	411,979		298,096	423,004		284,338
Change in unrealized investment gains and losses	(182,919)		61,869	(189,828)		75,867
Reclassification of net realized investment (gains) losses to net income	(8,392)		(3,861)	(12,508)		(4,101)
End of period	220,668		356,104	220,668		356,104
Equity securities [Member]
Reconciliation of net unrealized investment gains (losses) on fixed maturity securities and equity securities
Beginning of period	3,604		2,238	720		2,408
Change in unrealized investment gains and losses	1,291		882	4,519		727
Reclassification of net realized investment (gains) losses to net income	(1,629)		(2,577)	(1,973)		(2,592)
End of period	$ 3,266		$ 543	$ 3,266		$ 543

[1] All amounts are net of tax.

[2] The pretax amounts reclassified from accumulated other comprehensive income, $15,417 and $22,279, are included in net realized investment gains and the related tax expenses, $5,396 and $7,798, are included in income tax expense in the Consolidated Statements of Operations for the three and six months ended June 30, 2013, respectively.