Net Income (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, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
DSUs
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Units, potentially dilutive securities not included in the computation of diluted net loss per share (in shares)	23	45	23	45
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]
Units, potentially dilutive securities not included in the computation of diluted net loss per share (in shares)	307	505	307	505
Weighted Average Price per Share, anti-dilutive securities excluded from computation of earnings per share (in dollars per share)	$ 11.28	$ 10.56	$ 11.28	$ 10.56
Restricted stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Units, potentially dilutive securities not included in the computation of diluted net loss per share (in shares)	2,109	2,692	2,109	2,692
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