Acquisitions (Pro Forma Financial Information, Summary Of Results Of Operations) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Acquisitions [Abstract]
Total Revenue	$ 811,933	$ 800,476
Net income	$ 23,236	$ 51,818
Net income per share, Basic	$ 0.80	$ 1.75
Net income per share, Diluted	$ 0.79	$ 1.71