Statements of Equity (USD $) In Thousands, unless otherwise specified	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (loss) [Member]	Total Equity
Balance at Dec. 31, 2010		$ 2,500	$ 974,921	$ 621,830	$ 190,872	$ 1,790,123
Distribution to parent	587,831	0	(92,251)	(495,580)	0	(587,831)
Comprehensive income:
Net income	(151,555)	0	0	(151,555)	0	(151,555)
Other comprehensive income (loss), net of tax	(30,160)	0	0	0	(30,160)	(30,160)
Total comprehensive income (loss)						(181,715)
Balance at Dec. 31, 2011		2,500	882,670	(25,305)	160,712	1,020,577
Affiliated asset transfers		0	10,666	0	0	10,666
Distribution to parent	408,000	0	0	(408,000)	0	(408,000)
Comprehensive income:
Net income	634,059	0	0	634,059	0	634,059
Other comprehensive income (loss), net of tax	(13,425)	0	0	0	(13,425)	(13,425)
Total comprehensive income (loss)						620,634
Balance at Dec. 31, 2012		2,500	893,336	200,754	147,287	1,243,877
Affiliated asset transfers		0	8,086	0	0	8,086
Distribution to parent	284,000	0	0	(284,000)	0	(284,000)
Comprehensive income:
Net income	848,092	0	0	848,092	0	848,092
Other comprehensive income (loss), net of tax	(76,420)	0	0	0	(76,420)	(76,420)
Total comprehensive income (loss)						771,672
Balance at Dec. 31, 2013		$ 2,500	$ 901,422	$ 764,846	$ 70,867	$ 1,739,635