Consolidated Statements of Comprehensive Income (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement of Comprehensive Income [Abstract]
Net income	$ 63,145	$ 11,768	$ 185,442	$ 20,930
Other comprehensive income:
Net unrealized gain (loss) on securities	7,687	7,313	7,677	7,313
Reclassification of net realized (gain) loss on securities into earnings	(11,213)		(7,515)
Other comprehensive income	(3,526)	7,313	162	7,313
Comprehensive income	$ 59,619	$ 19,081	$ 185,604	$ 28,243