Equity Preferred Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Class of Stock [Line Items]
Depositary Shares, Issued	2,000,000	2,000,000
Preferred Stock, Par Value Per Share	$ 1.00	$ 1.00
Preferred Stock, Value, Issued	$ 47,753	$ 47,753
Preferred Stock, Redemption Terms	The Company may redeem the Series D preferred stock on any dividend payment date on or after June 15, 2018; or within 90 days of a change, proposed change, administrative decision, or re-interpretation in the laws, regulations, or guidelines regarding the regulatory capital treatment of the Series D preferred stock.
Series D Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Contract Terms	Each Depositary Share represents a 1/40th interest in a share
Preferred Stock, Dividend Rate, Percentage	6.95%
Preferred Stock, Par Value Per Share	$ 1.00
Preferred Stock, Liquidation Preference Per Share	$ 1,000	$ 1,000
Preferred Stock, Value, Issued	$ 47,753	$ 47,800