Shareholders' Equity - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Jul. 28, 2016	Dec. 31, 2015
Stockholders Equity Note [Line Items]
Investment subject to foreign currency fluctuations	$ 16,884,000		$ 16,884,000
Cumulative foreign currency translation loss, net of deferred income tax benefit	(34,869,000)		(34,869,000)			$ (37,702,000)
Income tax (benefit) expense	$ (11,930,000)	$ (5,387,000)	(35,373,000)	$ (27,346,000)
Foreign Currency Exchange Gain (Loss), Net
Stockholders Equity Note [Line Items]
Income tax (benefit) expense			0
ATM Program
Stockholders Equity Note [Line Items]
Proceeds from sale of common stock under ATM program			45,564,000
ATM Program | Cowen and Company LLC
Stockholders Equity Note [Line Items]
Aggregate offering price authorized					$ 75,000,000
Proceeds from sale of common stock under ATM program gross			46,612,000
Proceeds from sale of common stock under ATM program			45,564,000
Commissions paid			$ 1,048,000
ATM Program | Common Stock | Cowen and Company LLC
Stockholders Equity Note [Line Items]
Shares sold under ATM program			3,405,709
Average price per share	$ 13.69		$ 13.69