Income (loss) Per Common Share - Computation of Basic and Diluted Net Income (Loss) Per Common Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Numerator:
Net income (loss)	$ 23,670	$ (13,279)	$ (365)	$ (19,452)	$ 10,391	$ (19,817)
Adjustments for basic net income (loss) per common share:
Dividend accrued on redeemable preferred stock	(10,213)	$ (9,511)	(8,689)	$ (8,307)
Dividend requirements	(75)		(75)		(150)	(150)
Net income attributable to participating securities	(223)
Net income (loss) attributable to common stockholders	12,646		(9,634)		(10,507)	(37,972)
Dividends on Series B and Series D Preferred assumed to be converted, if dilutive	75
Numerator for diluted net income (loss) per common share	$ 12,721		$ (9,634)		$ (10,507)	$ (37,972)
Denominator:
Denominator for basic net income (loss) per common share - weighted- average shares	28,485,251		28,198,963		28,414,863	28,187,584
Effect of dilutive securities:
Convertible preferred stocks	916,666
Unvested restricted stock and stock units	741,784
Dilutive potential common shares	1,658,450
Denominator for diluted net income (loss) per common share - adjusted weighted-average shares	30,143,701		28,198,963		28,414,863	28,187,584
Net income (loss)	$ 0.44		$ (0.34)		$ (0.37)	$ (1.35)
Net income (loss)	$ 0.42		$ (0.34)		$ (0.37)	$ (1.35)
Series E Redeemable Preferred Stock [Member]
Adjustments for basic net income (loss) per common share:
Dividend accrued on redeemable preferred stock	$ (10,213)		$ (8,689)		$ (19,724)	$ (16,996)
Accretion of redeemable preferred stock	(513)		(505)		(1,024)	(1,009)
Series B Preferred Stock [Member]
Adjustments for basic net income (loss) per common share:
Dividend requirements	(60)		(60)		(120)	(120)
Series D Preferred Stock [Member]
Adjustments for basic net income (loss) per common share:
Dividend requirements	$ (15)		$ (15)		$ (30)	$ (30)