Shareholders' Equity (Tables)

12 Months Ended

Dec. 31, 2011

Shareholders' Equity [Abstract]

Summary Of Activities In Common Stock

	Years ended December 31,
	2011						2010						2009
	Shares			Amount			Shares			Amount			Shares			Amount
Purchases of common stock		(3,004	)	$	(71,802	)		(3,559	)	$	(65,793	)		(1,235	)	$	(17,000	)
Stock option exercises		582			3,553			615			3,181			425			2,295
Employee stock plan purchases		100			2,045			118			1,825			115			1,428