Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Available-For-Sale Securities, Amortized Cost	$ 1,297,282	$ 1,244,972
Held-to-Maturity Securities, Fair Value	$ 321,917	$ 184,822
Preferred stock, par value	$ 1.00	$ 1.00
Preferred stock, shares authorized	100,000	100,000
Preferred stock, shares issued
Preferred stock, shares outstanding
Class A common stock
Common stock, shares authorized	10,000,000	10,000,000
Common stock, shares issued	3,556,429	3,548,317
Common stock, par value	$ 1.00	$ 1.00
Class B common stock
Common stock, shares authorized	5,000,000	5,000,000
Common stock, shares issued	1,991,880	1,994,380
Common stock, par value	$ 1.00	$ 1.00