Business Acquisition Business Acquisitions (Supplementary Information On Unaudited Pro Forma Financial Results Of Acquisition) (Details) (2014 Business Acquisitions [Member], USD $) In Thousands, except Per Share data, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
2014 Business Acquisitions [Member]
Business Acquisition, Pro Forma Revenue	$ 474,749	$ 440,030
Business Acquisition, Pro Forma Net Income (Loss)	$ 96,031	$ 89,043
Business Acquisition, Pro Forma Earnings Per Share, Basic	$ 2.01	$ 1.93
Business Acquisition, Pro Forma Earnings Per Share, Diluted	$ 2.00	$ 1.90