Business Concentrations and Credit Risk (Detail)	3 Months Ended
	Mar. 31, 2013
Concentration Risk, Customer	For the three months ended March 31, 2013 and 2012, no individual client accounted for 10% or more of consolidated revenue. As of March 31, 2013, no individual client accounted for more than 10% of our gross accounts receivable balance. As of March 31, 2012, one individual client accounted for more than 10% of our gross accounts receivable.