Estimated Fair Values and Useful Lives of Intangible Assets Acquired (Detail) (Thoughtcorp Inc, USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012
Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	$ 5,296
Client relationships
Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	2,810
Weighted Average Useful Life	15 years
Trade Name
Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	2,014
Weighted Average Useful Life	5 years
Noncompete Agreements
Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	$ 472
Weighted Average Useful Life	5 years