Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Amortized cost of available-for-sale securities	$ 430,836	$ 306,193
Preferred stock, par value	$ 1	$ 1
Preferred stock, shares authorized	15,000,000	15,000,000
Preferred stock, shares issued	0	7,500,000
Common stock, no par value
Common stock, shares authorized	2,500,000,000	2,500,000,000
Common stock, shares issued	21,102,668	114,244
Preferred Stock Series A [Member]
Preferred stock, par value	$ 10.00	$ 10.00
Preferred stock, shares authorized	200,000	200,000
Preferred stock, shares issued	0	51,500
Preferred stock, shares outstanding	0	51,500
Preferred stock, stated value	$ 1,000	$ 1,000