Business Acquisition Business Acquisitions (Supplementary Information On Unaudited Pro Forma Financial Results Of Acquisition) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
2012 Business Acquisitions [Member]
Business Acquisition, Pro Forma Revenue		$ 417,250
Business Acquisition, Pro Forma Net Income (Loss)		120,210
Business Acquisition, Pro Forma Earnings Per Share, Basic		$ 2.60
Business Acquisition, Pro Forma Earnings Per Share, Diluted		$ 2.58
2013 Business Acquisitions [Member]
Business Acquisition, Pro Forma Revenue	545,952	470,190
Business Acquisition, Pro Forma Net Income (Loss)	$ 108,600	$ 122,187
Business Acquisition, Pro Forma Earnings Per Share, Basic	$ 2.34	$ 2.64
Business Acquisition, Pro Forma Earnings Per Share, Diluted	$ 2.31	$ 2.62