Common And Preferred Stock (Details) (USD $)	0 Months Ended	1 Months Ended	3 Months Ended
	Dec. 06, 2011	Apr. 21, 2008	Mar. 31, 2012	Dec. 31, 2011
Common And Preferred Stock [Abstract]
Share repurchase authorized amount	$ 50,000,000	$ 75,000,000	$ 125,000,000
Purchase of common stock (in shares)			200,000
Purchase of common stock			$ 10,183,000
Common stock, shares authorized			150,000,000	150,000,000
Common stock, par value			$ 0.01	$ 0.01
Preferred stock, shares authorized			5,000,000	5,000,000
Preferred stock, par value			$ 0.01	$ 0.01
Preferred stock, shares issued			0	0