CONSOLIDATED STATEMENT OF CHANGES IN SHAREHOLDERS' EQUITY (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Dividends declared:
Dividends declared per common share (in dollars per share)	$ 1.06	$ 1.00	$ 0.94
Common stock issued under employee stock plan, tax benefits	$ 1,524	$ 703	$ 842