Employee Benefit Plans - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Employee contribution percentage	60.00%
Employee contribution amount	$ 17,000
Contribution expense recognized by Indian entities	566,000	538,000
Expected amortization out of comprehensive income	10,000
Provident Fund
Defined Benefit Plan Disclosure [Line Items]
Contribution expense recognized by Indian entities	3,700,000	3,280,000	2,790,000
Gratuity Plan
Defined Benefit Plan Disclosure [Line Items]
Contribution expense recognized by Indian entities	2,300,000	2,300,000	1,400,000
Accrued liability for retirement plan	$ 8,200,000	$ 5,600,000