Capital Purchase Program (Details) - $ / shares		12 Months Ended
	Jan. 30, 2009	Dec. 31, 2009	Sep. 30, 2015	Dec. 31, 2014
Equity, Class of Treasury Stock [Line Items]
Warrants issued under capital repurchase program (in shares)	208,202	104,101
Common stock, par value (in dollars per share)	$ 2.50		$ 2.50	$ 2.50
Exercise price of warrants (in dollars per share)	$ 15.85
Series A Cumulative Perpetual Preferred Stock [Member]
Equity, Class of Treasury Stock [Line Items]
Preferred stock issued under capital repurchase program (in shares)	22,000
Preferred stock, par value (in dollars per share)	$ 2.50
Liquidation preference per share (in dollars per shares)	$ 1,000
Shares redeemed during period (in shares)		22,000