Income Taxes (Details) (USD $)	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Income Taxes (Textuals) [Abstract]
Income before income tax	$ 136,951,000	$ 125,449,000	$ 267,577,000	$ 237,430,000
Provision for income taxes	(38,227,000)	(33,645,000)	(71,857,000)	(65,420,000)
Effective tax rate	27.90%	26.80%	26.90%	27.60%
Increase in unrecognized tax benefits for the period			4,400,000
Unrecognized tax benefits minimum amount of estimated reduction within the next twelve months	8,300,000		8,300,000
Unrecognized tax benefits maximum amount of estimated reduction within the next twelve months	$ 23,100,000		$ 23,100,000

Sum of operating profit and nonoperating income (expense) before, income taxes, extraordinary items, cumulative effects of changes in accounting principles, and noncontrolling interest.

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- Definition

Income taxes.

+ Details

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- Definition

Significant change in unrecognized tax benefits is reasonably possible estimated range of change maximum.

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- Definition

Significant change in unrecognized tax benefits is reasonably possible estimated range of change minimum.

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- Definition

A ratio calculated by dividing the reported amount of income tax expense attributable to continuing operations for the period by GAAP-basis pretax income from continuing operations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 109
-Paragraph 47

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 08
-Paragraph h
-Subparagraph 2
-Article 4

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- Definition

The sum of the current income tax expense (benefit) and the deferred income tax expense (benefit) pertaining to continuing operations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 08
-Paragraph h
-Article 4

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 109
-Paragraph 45
-Subparagraph a, b

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- Definition

The net amount of all increases and decreases in unrecognized tax benefits for the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
-Number 48
-Paragraph 21
-Subparagraph a

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