Basic and Diluted Loss Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net income (loss)		$ 11,723	$ (24,677)	$ 12,185	$ (39,245)
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic And Diluted	[1]	108	0	107	0
Net Income (Loss) Available to Common Stockholders, Basic		$ 11,615	$ (24,677)	$ 12,078	$ (39,245)
Basic weighted-average common stock shares outstanding		37,339,000	30,406,000	37,261,000	30,388,000
Add dilutive effects of common stock equivalents	[2]	$ 24	$ 0	$ 58	$ 0
Diluted weighted-average common stock outstanding (in shares)		37,363,000	30,406,000	37,319,000	30,388,000
Income (loss) per common share, basic (USD per share)		$ 0.31	$ (0.81)	$ 0.32	$ (1.29)
Income (loss) per common share, diluted (USD per share)		$ 0.31	$ (0.81)	$ 0.32	$ (1.29)
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average number of shares issuable under the common stock warrants (in shares)		749,148	790,683	749,148	790,683	749,148
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Antidilutive securities excluded from computation of earnings per share (shares)		348,000	658,000	331,000	658,000
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Antidilutive securities excluded from computation of earnings per share (shares)		24,000		58,000

[1] Participating securities includes restricted stock that has been issued but is not yet vested.

[2] Entities with a net loss are prohibited from including potential common shares in the computation of diluted per share amounts; therefore, we have utilized the basic shares outstanding to calculate both basic and diluted loss per share for the three and six months ended June 30, 2014.