Stockholders' Equity (Schedule Of Deferred Stock Units Transactions) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Outstanding	369,133	266,216	231,113
Issued	23,713	79,714	31,803
Granted	282,925	53,450	20,000
Dividend equivalents	34,568		15,521
Forfeited		(2,660)
Exercised	(96,585)	(27,587)	(32,221)
Outstanding	613,754	369,133	266,216
Stock Price, Granted		$ 23.17	$ 20.89
Stock Price, Dividend equivalent	$ 33.32		$ 23.49
Minimum [Member]
Stock Price, Outstanding	$ 5.50	$ 5.50	$ 5.50
Stock Price, Issued	$ 24.53	$ 18.67	$ 20.13
Stock Price, Granted	$ 26.54
Stock Price, Forfeited		$ 20.89
Stock Price, Exercised	$ 5.50	$ 6.16	$ 5.50
Stock Price, Outstanding	$ 6.16	$ 5.50	$ 5.50
Maximum [Member]
Stock Price, Outstanding	$ 40.68	$ 40.68	$ 40.68
Stock Price, Issued	$ 32.07	$ 25.48	$ 25.06
Stock Price, Granted	$ 30.50
Stock Price, Forfeited		$ 23.49
Stock Price, Exercised	$ 40.68	$ 25.06	$ 21.90
Stock Price, Outstanding	$ 33.32	$ 40.68	$ 40.68