Consolidated Statements of Stockholders' Equity (Parenthetical) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash dividends on preferred stock, rate	2.96%	3.85%	5.00%
Cash dividends on common stock, per share	$ 0.42	$ 0.38	$ 0.31
Retained Earnings [Member]
Cash dividends on preferred stock, rate	2.96%	3.85%	5.00%
Cash dividends on common stock, per share	$ 0.42	$ 0.38	$ 0.31