Preferred Stock (Details) (USD $) In Thousands, except Share data, unless otherwise specified	6 Months Ended		0 Months Ended
	Jun. 30, 2013	Dec. 31, 2012	Jun. 19, 2013 Series C Preferred Stock	Mar. 19, 2013 Series C Preferred Stock	Mar. 19, 2013 Depositary share
Preferred Stock
Shares issued (in shares)				135,000	5,400,000
Per share interest in Non-Cumulative Perpetual Preferred Stock, Series C					0.025
Dividend rate (as a percent)				6.50%
Par value (in dollars per share)	$ 1.00	$ 1.00
Liquidation preference (in dollars per share)				$ 1,000	$ 25
Aggregate proceeds from the offering, net of underwriting discounts and other issuance costs	$ 129,796			$ 129,800
Redemption price (in dollars per share)				$ 1,000	$ 25
Dividends on preferred stock	$ 2,827		$ 2,800
Dividends declared on preferred stock (in dollars per share)	$ 20.94		$ 20.94