Net Loss per Share - Potentially Dilutive Securities Not Included in Computation of Diluted Net Loss Per Share (Detail) - $ / shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
DSUs
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities not included in the computation of diluted net loss per share (in shares)	45	90	45	90
Weighted Average Price per Share, anti-dilutive securities excluded from computation of earnings per share (in dollars per share)	$ 0.00	$ 0.00	$ 0.00	$ 0.00
SARs
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities not included in the computation of diluted net loss per share (in shares)	505	542	505	542
Weighted Average Price per Share, anti-dilutive securities excluded from computation of earnings per share (in dollars per share)	$ 10.56	$ 10.64	$ 10.56	$ 10.64
Restricted Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities not included in the computation of diluted net loss per share (in shares)	2,692	3,586	2,692	3,586
Weighted Average Price per Share, anti-dilutive securities excluded from computation of earnings per share (in dollars per share)	$ 0.00	$ 0.00	$ 0.00	$ 0.00