Basis of Presentation (Details)	Mar. 31, 2012	Mar. 31, 2011
Basis of Presentation [Abstract]
Percentage of PEO revenues from the Company's Texas markets (in hundredths)	26.00%	27.00%
Percentage of PEO revenues from the Company's California markets (in hundredths)	17.00%	16.00%

A presentation of the revenue percentage from the state of California

No definition available.

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Namespace Prefix:	nsp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant