Income (Loss) Per Common Share - Computation of Basic and Diluted Net Income Per Common Share (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Numerator:
Net income (loss)	$ 11,641	$ (68)
Total dividends on preferred stocks	(300)	(300)
Numerator for basic net income (loss) per common share-net income (loss) applicable to common stock	11,341	(368)
Dividends on preferred stocks assumed to be converted, if dilutive	300
Numerator for diluted net income (loss) per common share	11,641	(368)
Denominator:
Denominator for basic net income (loss) per common share-weighted-average shares	22,532,522	22,423,616
Effect of dilutive securities:
Convertible preferred stocks	916,666
Stock options	190,519
Dilutive potential common shares	1,107,185
Denominator for diluted net income (loss) per common share-adjusted weighted-average shares and assumed conversions	23,639,707	22,423,616
Basic net income (loss) per common share	$ 0.50	$ (0.02)
Diluted net income (loss) per common share	$ 0.49	$ (0.02)
Series B Preferred Stock [Member]
Numerator:
Total dividends on preferred stocks	(240)	(240)
Series D Preferred Stock [Member]
Numerator:
Total dividends on preferred stocks	$ (60)	$ (60)