Convertible Senior Notes - Additional Information (Detail)				1 Months Ended	12 Months Ended
	Dec. 23, 2015 USD ($)	Dec. 23, 2013 USD ($)	Dec. 17, 2013 USD ($) shares	Dec. 31, 2016 USD ($) open_market_purchase $ / shares shares	Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Debt Instrument [Line Items]
Payments for repurchase					$ 9,014,000	$ 0	$ 0
2018 Convertible Notes [Member]
Debt Instrument [Line Items]
Debt instrument face value				$ 101,800,000	101,800,000	105,100,000
Principal amount				$ 110,037,000	$ 110,037,000	$ 120,000,000
2.75% Convertible Senior Notes Due 2018 [Member]
Debt Instrument [Line Items]
Sale of convertible notes, principal amount			$ 120,000,000
Interest rate					2.75%
Common shares converted value (shares) | shares			120,000	9,963	11,400,000
Conversion rate (shares) | shares					95
Conversion rate, price per $1,000 | $ / shares				$ 1,000	$ 1,000
Money conversion price per share ($ per share) | $ / shares				$ 10.53	$ 10.53
Net proceeds from convertible notes		$ 115,400,000
Professional fee			$ 4,600,000
Additional paid-in capital	$ 13,100,000
Number Of open market purchases | open_market_purchase				2
Repurchase of principal				$ 10,000,000
Payments for repurchase				9,000,000
Loss on 2018 Convertible Note purchase (Note 15)					$ 25,000
Proceeds from unwinding					21,000
Debt instrument face value				$ 110,000,000	$ 110,000,000
Strike price per share ($ per share) | $ / shares				$ 14.03	$ 14.03
Threshold percentage of conversion price					130.00%
Convertible senior notes trading price				$ 1,000	$ 1,000
Percentage of product of last reported sale price of common stock					98.00%
2.75% Convertible Senior Notes Due 2018 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Debt convertible trading days					20 days
Debt convertible consecutive trading days					5 days
2.75% Convertible Senior Notes Due 2018 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Debt convertible consecutive trading days					30 days