Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Held-to-maturity Securities, Fair Value	$ 319	$ 6,699
Statement of Financial Position [Abstract]
Common stock, par value	$ 2.5	$ 2.5
Common stock, shares authorized	600,000,000	600,000,000
Common stock, shares issued	216,800,000	216,200,000
Treasury stock, shares	17,600,000	16,000,000