Employee Benefit Plans - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Employee contribution percentage	60.00%
Employee contribution amount	$ 17,500
Defined Benefit Plan, contributions by employer	0
Contribution expense recognized by Indian entities	814,000	703,000
Expected amortization out of comprehensive income	70,000
Provident Fund
Defined Benefit Plan Disclosure [Line Items]
Contribution expense recognized by Indian entities	4,700,000	3,300,000	3,700,000
Gratuity Plan
Defined Benefit Plan Disclosure [Line Items]
Contribution expense recognized by Indian entities	3,100,000	2,900,000	2,300,000
Accrued liability for retirement plan	$ 12,100,000	$ 8,900,000