Business Combinations (Results Of Operations) (Details) (USD $) In Thousands, except Share data	3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended
Sep. 30, 2010 2010 Acquisition [Member]	Sep. 30, 2009 2010 Acquisition [Member]	Sep. 30, 2010 2010 Acquisition [Member]	Sep. 30, 2009 2010 Acquisition [Member]	Sep. 30, 2011 2011 Acquisitions [Member]	Sep. 30, 2010 2011 Acquisitions [Member]	Sep. 30, 2011 2011 Acquisitions [Member]	Sep. 30, 2010 2011 Acquisitions [Member]
Business Acquisition [Line Items]
Total revenues	$ 251,913	$ 255,097	$ 769,369	$ 789,415	$ 261,015	$ 260,735	$ 782,561	$ 783,433
Income before income taxes	74,060	70,627	221,088	223,763	72,933	77,284	215,159	227,040
Net income	$ 44,915	$ 42,864	$ 133,817	$ 135,760	$ 44,319	$ 47,501	$ 130,119	$ 137,420
Net income per share, Basic	$ 0.32	$ 0.30	$ 0.94	$ 0.96	$ 0.31	$ 0.33	$ 0.91	$ 0.97
Net income per share, Diluted	$ 0.31	$ 0.30	$ 0.93	$ 0.96	$ 0.31	$ 0.33	$ 0.90	$ 0.96
Weighted average number of shares outstanding, Basic	138,093	137,279	137,802	137,052	138,690	138,093	138,475	137,802
Weighted average number of shares outstanding, Diluted	139,507	137,671	139,128	137,403	140,443	139,507	140,120	139,128

Business acquisition, pro forma earnings per share, weighted average number of basic shares outstanding.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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+ References

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