Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Net cash flows provided by (used in) operating activities	$ 162,138	$ 631,946
Fixed maturity securities:
Purchases	(923,704)	(1,349,745)
Sales	525,523	685,980
Maturities	514,725	325,750
Net sales (purchases) of short-term investments	(108,014)	(49,901)
Net proceeds from paydowns on financial guaranty variable interest entities' assets	282,790	423,977
Acquisition of MIAC, net of cash acquired	(91,094)	0
Other	73,232	8,696
Net cash flows provided by (used in) investing activities	273,458	44,757
Financing activities
Proceeds from issuances of common stock	172,500	0
Dividends paid	(32,878)	(16,577)
Repurchases of common stock	(24,313)	0
Share activity under option and incentive plans	(2,209)	(2,652)
Net paydowns of financial guaranty variable interest entities' liabilities	(388,576)	(593,294)
Repayment of long-term debt	(195,668)	(10,294)
Net cash flows provided by (used in) financing activities	(471,144)	(622,817)
Effect of exchange rate changes	(3,649)	3,215
Increase (decrease) in cash	(39,197)	57,101
Cash at beginning of period	214,544	108,389
Cash at end of period	175,347	165,490
Cash paid (received) during the period for:
Income taxes	(15,500)	89,202
Interest	$ 46,787	$ 45,711