Other Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011	Sep. 30, 2012		Sep. 30, 2011	Dec. 31, 2011
Other comprehensive income (before tax) [Abstract]
Change in unrealized gains and losses on investments	$ 47,368		$ 74,142	$ 10,243		$ 111,355
Unrealized foreign currency translation adjustment	1,709		(15,422)	2,260		(8,459)
Other comprehensive income (loss)	49,077		58,720	12,503		102,896
Other comprehensive income (tax) [Abstract]
Change in unrealized gains and losses on investments	(16,552)		(25,705)	(3,462)		(38,601)
Unrealized foreign currency translation adjustment	(600)		5,401	(792)		2,962
Other comprehensive income (loss)	(17,152)		(20,304)	(4,254)		(35,639)
Other comprehensive income (valuation allowance) [Abstract]
Change in unrealized investment gains and losses, net	13,671		0	0		0
Other comprehensive income (loss)	13,671		0	0		0
Other comprehensive income (net of tax) [Abstract]
Change in unrealized investment gains and losses, net (notes 7 and 8)	44,487		48,437	6,781		72,754
Unrealized foreign currency translation adjustment	1,109		(10,021)	1,468		(5,497)
Other comprehensive income (loss)	45,596		38,416	8,249		67,257
Accumulated other comprehensive income (loss) [Abstract]
Unrealized gains (losses) on investments	130,330			130,330			120,087
Defined benefit plans	(70,582)			(70,582)			(70,582)
Foreign currency translation adjustment	32,554			32,554			30,294
Accumulated other comprehensive income before tax	92,302			92,302			79,799
Tax Effect	(53,929)	[1]		(53,929)	[1]		(49,675)	[1]
Total accumulated other comprehensive income (loss), net of tax	$ 38,373			$ 38,373			$ 30,124

[1] Tax effect does not approximate 35% due to amounts of tax benefits not provided in various periods due to our tax valuation allowance.