Employee Benefit Plan - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Percentage of contribution to 401(k) defined contribution retirement savings plan by employer	50.00%
Percentage of contribution to 401(k) defined contribution retirement savings plan by each employee	5.00%
Maximum
Defined Benefit Plan Disclosure [Line Items]
Employer 401(k) annual matching contribution to each employee	$ 1,750
Foreign Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer for defined contribution plans	800,000	800,000	700,000
Defined Contribution Pension Plan 401k
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer for defined contribution plans	$ 2,800,000	$ 2,600,000	$ 2,300,000