Income Taxes (Details 2)	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Effective tax rate reconciliation
Statutory U.S. federal tax rate	35.00%	35.00%	35.00%
Increase (decrease) in rate resulting from:
Effect of qualified domestic production deduction	(1.60%)	(1.10%)	(0.40%)
Effect of Patient Protection and Affordable Care Act		1.40%
State and local income taxes, net of related federal taxes	2.70%	2.50%	2.80%
Other, net	(1.60%)	(0.10%)	(1.70%)
Effective tax rate	34.50%	37.70%	35.70%

Effective income tax rate reconciliation patient protection and affordable care act.

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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 domestic federal statutory tax rate applicable under enacted tax laws to the Company's pretax income from continuing operations for the period. The "statutory" tax rate shall be the regular tax rate if there are alternative tax systems.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 109

-Paragraph 47

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- Definition

The portion of the difference between the effective income tax rate and domestic federal statutory income tax rate attributable to the deduction for qualified production activities received under enacted tax laws.

+ References

No definition available.

+ Details

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- Definition

The portion of the difference between the effective income tax rate and domestic federal statutory income tax rate attributable to all other items not otherwise listed in the existing taxonomy.

+ References

No definition available.

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- Definition

The portion of the difference between the effective income tax rate and domestic federal statutory income tax rate that can be explained by the state and local income tax expense (benefit), net of the federal tax benefit (expense) thereon, recorded during the period.

+ References

No definition available.

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