Segment Information - Additional Information (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Segment Reporting Information [Line Items]
Number of geographic regions considered as reportable operating segments			3
Customer Concentration Risk
Segment Reporting Information [Line Items]
Percentage of revenues	No single customer accounted for more than 10% of the Company's consolidated revenues during the three months and nine ended September 30, 2012 and 2011.	No single customer accounted for more than 10% of the Company's consolidated revenues during the three months and nine ended September 30, 2012 and 2011.	No single customer accounted for more than 10% of the Company's consolidated revenues during the three months and nine ended September 30, 2012 and 2011.	No single customer accounted for more than 10% of the Company's consolidated revenues during the three months and nine ended September 30, 2012 and 2011.
Geographic Concentration Risk
Segment Reporting Information [Line Items]
Percentage of revenues	No other country outside the United States accounted for more than 10% of the Company’s consolidated revenues during the three and nine months ended September 30, 2012.	No other country outside the United States accounted for more than 10% of the Company’s consolidated revenues during the three and nine months ended September 30, 2012.	No other country outside the United States accounted for more than 10% of the Company’s consolidated revenues during the three and nine months ended September 30, 2012.	No other country outside the United States accounted for more than 10% of the Company’s consolidated revenues during the three and nine months ended September 30, 2012.
United Kingdom
Segment Reporting Information [Line Items]
Percentage of revenues				Aggregate revenues attributable to customers in the United Kingdom accounted for 10.1% of the Company's consolidated revenues during the nine months ended September 30, 2011.