Summary of Significant Accounting Policies- Additional Information (Detail)	12 Months Ended
	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($) Derivative	Nov. 30, 2016 USD ($)	Dec. 31, 2013 USD ($)
Significant Accounting Policies [Line Items]
Other comprehensive income	$ (19,300,000)	$ (49,400,000)	$ (31,900,000)
Other comprehensive income, foreign currency translation adjustments	19,000,000	45,400,000	32,400,000
Cash and cash equivalents	78,332,000	500,499,000	197,708,000		$ 178,757,000
Non current term deposits with banks	225,000	77,000
Term deposits	6,600,000	413,600,000
Depreciation and amortization expense	14,700,000	15,600,000	16,100,000
Foreign exchange gain (loss)	8,300,000	18,100,000	10,700,000
Unutilized earned leave expense	3,400,000	5,300,000	5,400,000
Accrual for unutilized earned leave	23,100,000	22,400,000
Deferred income taxes and other non-current assets	67,346,000	72,170,000
Other current assets	36,306,000	36,423,000
Accrued liabilities	20,799,000	23,150,000
Restricted Deposits
Significant Accounting Policies [Line Items]
Term deposits	440,000	600,000
Foreign Exchange Forward
Significant Accounting Policies [Line Items]
Derivate Notional Amount			160,000,000
Derivative contracts expired			160,000,000
Gain on expiration of contracts			$ 4,560,000
Foreign exchange forward contracts outstanding | Derivative			0
Foreign Exchange Forward | Minimum
Significant Accounting Policies [Line Items]
Foreign exchange forward contracts, maximum maturity date			1 month
Foreign Exchange Forward | Maximum
Significant Accounting Policies [Line Items]
Foreign exchange forward contracts, maximum maturity date			6 months
ASU 2015-17 | Restatement Adjustment
Significant Accounting Policies [Line Items]
Deferred income taxes and other non-current assets		8,150,000
Other non-current liabilities		60,000
Other current assets		(8,150,000)
Accrued liabilities		$ (60,000)
Cash flow Hedge | Interest Rate Swap
Significant Accounting Policies [Line Items]
Derivate Notional Amount	$ 300,000,000			$ 300,000,000