Summary Of Operations And Significant Accounting Policies (Reconciliation Of Shares Used In Calculating Basic and Diluted Earnings Per Share) (Details)	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Summary Of Operations And Significant Accounting Policies [Abstract]
Basic	55,892,061	55,688,824	55,146,901	54,419,498	53,563,396	53,109,824	52,735,556	52,080,363	55,292,597	52,876,999	50,721,880
Effect of assumed exercised options									1,838,444	2,131,743	2,185,661
Diluted	57,589,248	57,760,868	57,150,256	56,389,729	55,756,350	55,736,089	55,553,247	54,805,222	57,131,041	55,008,742	52,907,541