Statement Of Changes In Shareholders' Equity (USD $) In Thousands	Common Stock Amount [Member]	Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income [Member]	Total
Balance at Dec. 31, 2010	$ 46	$ 1,043,027	$ (3,480)	$ 105,891	$ 1,145,484
Issuance of common stock	31	853,410			853,441
Share based compensation		735			735
Dividends declared on common stock			(209,710)		(209,710)
Comprehensive income:
Net income			213,749		213,749
Other comprehensive income:
Net unrealized gain on securities available for sale				182,904	182,904
Net unrealized loss on derivative instruments				(171,600)	(171,600)
Comprehensive income					225,053
Balance at Sep. 30, 2011	$ 77	$ 1,897,172	$ 559	$ 117,195	$ 2,015,003