Shareholders' Equity - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016	Jul. 28, 2016
Stockholders Equity Note [Line Items]
Investment subject to foreign currency fluctuations	$ 15,950,000
Cumulative foreign currency translation loss, net of deferred income tax benefit	(32,622,000)		$ (34,326,000)
Income tax (benefit) expense	288,000	$ (12,101,000)
Foreign Currency Exchange Gain (Loss), Net
Stockholders Equity Note [Line Items]
Income tax (benefit) expense	0
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