Summary of Significant Accounting Policies - Reconciliation of Weighted Average Shares Used in Computation of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share Disclosure [Line Items]
Income available to common stockholders									$ (42,368)	$ (83,085)	$ 1,243
Assumed conversion of convertible senior notes									0	0	0
Income available to common stockholders plus assumed exercises and conversion									$ (42,368)	$ (83,085)	$ 1,243
Earnings per share - basic, Weighted Average Shares
Basic weighted number of shares (in shares)	23,106	23,106	23,106	23,100	22,799	22,772	21,616	18,104	23,104	21,341	16,542
Effect of dilutive securities:
Assumed conversion of convertible senior notes (in shares)									0	0	0
Earnings per share - diluted, Weighted Average Shares
Diluted weighted number of shares (in shares)	23,106	45,686	23,106	23,100	22,799	22,772	21,616	18,104	23,104	21,341	16,665
Earnings per share - basic
Net income (loss) attributable to common stockholders, per-share	$ (0.14)	$ 0.68	$ (0.80)	$ (1.57)	$ (1.33)	$ (0.77)	$ (0.77)	$ (1.01)	$ (1.83)	$ (3.89)	$ 0.08
Earnings per share - diluted
Diluted earnings (loss) per share (in dollars per share)	$ (0.14)	$ 0.38	$ (0.80)	$ (1.57)	$ (1.33)	$ (0.77)	$ (0.77)	$ (1.01)	$ (1.83)	$ (3.89)	$ 0.07
Options and warrants
Earnings Per Share Disclosure [Line Items]
Effect of dilutive securities, Options, warrants,unvested restricted stock grants and unvested performance stock grants									$ 0	$ 0	$ 0
Effect of dilutive securities:
Options and warrants (in shares)									0	0	0
Performance Stock
Earnings Per Share Disclosure [Line Items]
Effect of dilutive securities, Options, warrants,unvested restricted stock grants and unvested performance stock grants									$ 0	$ 0	$ 0
Effect of dilutive securities:
Unvested stock grants (in shares)									0	0	0
Restricted Stock
Earnings Per Share Disclosure [Line Items]
Effect of dilutive securities, Options, warrants,unvested restricted stock grants and unvested performance stock grants									$ 0	$ 0	$ 0
Effect of dilutive securities:
Unvested stock grants (in shares)									0	0	123