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Basis of Presentation (Details)	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Percentage of PEO revenues from the Company's Texas markets (in hundredths)	26.00%	26.00%
Percentage of PEO revenues from the Company's California markets (in hundredths)	18.00%	17.00%

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- Definition

A presentation of the revenue percentage from the state of California.

+ References

No definition available.

+ Details

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- Definition

A presentation of the revenue percentage from the state of Texas.

+ References

No definition available.

+ Details

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Namespace Prefix:	nsp_
Data Type:	num:percentItemType
Balance Type:	na
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- Details

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