CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (USD $) In Thousands	Total	Common stock [Member]	Paid-in capital [Member]	Treasury stock [Member]	Accumulated other comprehensive income (loss) [Member]	Retained earnings [Member]	Comprehensive income (loss) [Member]
Balance at Dec. 31, 2008		$ 130,119	$ 367,067	$ (276,873)	$ (106,789)	$ 2,253,676
Cumulative effect of accounting change (convertible debt)		0	73,475	0	0	(6,442)
Balance (as adjusted)		130,119	440,542	(276,873)	(106,789)	2,247,234
Net loss	(1,322,277)					(1,322,277)	(1,322,277)
Change in unrealized investment gains and losses, net (note 6)	154,358	0	0	0	154,358	0	154,358
Noncredit component of impairment losses, net (note 6)		0	0	0	(1,764)	0	(1,764)
Common stock shares issued upon debt conversion (note 8)		44	263	0	0	0
Reissuance of treasury stock, net (note 15)		0	(11,613)	7,135	0	(545)
Equity compensation (note 18)		0	14,102	0	0	0
Defined benefit plan adjustments, net (note 13)	10,704	0	0	0	10,704	0	10,704
Unrealized foreign currency translation adjustment, net	17,646	0	0	0	17,646	0	17,646
Other		0	0	0	0	295
Comprehensive loss	(1,141,333)						(1,141,333)
Balance at Dec. 31, 2009		130,163	443,294	(269,738)	74,155	924,707
Net loss	(363,735)					(363,735)	(363,735)
Change in unrealized investment gains and losses, net (note 6)	(69,074)	0	0	0	(69,074)	0	(69,074)
Common stock shares issued (note 15)		74,884	697,492	0	0	0
Reissuance of treasury stock, net (note 15)		0	(14,425)	47,106	0	(35,410)
Equity compensation (note 18)		0	12,581	0	0	0
Defined benefit plan adjustments, net (note 13)	6,390	0	0	0	6,390	0	6,390
Unrealized foreign currency translation adjustment, net	10,665	0	0	0	10,665	0	10,665
Comprehensive loss	(415,754)						(415,754)
Balance at Dec. 31, 2010	1,669,055	205,047	1,138,942	(222,632)	22,136	525,562
Net loss	(485,892)					(485,892)	(485,892)
Change in unrealized investment gains and losses, net (note 6)	21,057	0	0	0	21,057	0	21,057
Reissuance of treasury stock, net (note 15)		0	(14,577)	60,090	0	(51,305)
Equity compensation (note 18)		0	11,456	0	0	0
Defined benefit plan adjustments, net (note 13)	(12,862)	0	0	0	(12,862)	0	(12,862)
Unrealized foreign currency translation adjustment, net	(207)	0	0	0	(207)	0	(207)
Comprehensive loss	(477,904)						(477,904)
Balance at Dec. 31, 2011	$ 1,196,815	$ 205,047	$ 1,135,821	$ (162,542)	$ 30,124	$ (11,635)