Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Investment securities:
Held-to-maturity, estimated fair value	$ 51	$ 53
Stockholders' Equity
Convertible preferred stock, par value (in dollars per share)	$ 0	$ 0
Convertible preferred stock, authorized (in shares)	1,000,000	1,000,000
Convertible preferred stock, issued (in shares)	8,777	4,927
Common stock, par value (in dollars per share)	$ 4	$ 4
Common stock, authorized (in shares)	18,000,000	18,000,000
Common stock, issued (in shares)	7,553,094	7,477,132
Treasury stock (in shares)	1,546,529	1,418,456