Consolidated Statements of Stockholders' Equity (Parenthetical) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Deferred compensation plan held Rabbi Trust	33,461	30,597	29,596
Share issued under the performance incentive plan withheld for employee taxes	5,670	12,234	17,695
Cash Dividends Declared Per Share of Common Stock	$ 1.440	$ 1.365	$ 1.305