Condensed Consolidated Statements of Stockholders' Equity (Unaudited) (Parenthetical) (USD $) In Thousands, except Share data	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2011	Sep. 30, 2011	Dec. 31, 2010	Sep. 30, 2011
Condensed Consolidated Statements of Stockholders' Equity [Abstract]
Deferred compensation plan held Rabbi Trust		29,596		30,335
Tax expense recognized on the prior service cost component of employees benefit plans		$ 4	$ 5
Tax expense (benefit) recognized on the net gain (loss) component of employee benefit plans		$ 359	$ (541)
Shares issued under the performance incentive plan withheld for employee taxes	12,324	12,324	17,695
Cash Dividends Declared Per Share of Common Stock	$ 0.345	$ 1.020	$ 1.305