Computation of Basic and Diluted Net Income Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Earnings Per Share [Abstract]
Net income	$ 24,263	$ 6,747	$ 7,919
Preferred stock tax distributions	(320)	(1,073)	(402)
Basic EPS
Net income attributable to common stockholders	23,943	5,674	7,517
Effect of Dilutive Securities
Preferred stock	320	1,073	402
Diluted EPS
Net income attributable to common stockholders	$ 24,263	$ 6,747	$ 7,919
Basic EPS, Shares
Net income attributable to common stockholders, shares	73,571	40,681	31,320
Effect of Dilutive Securities, shares
Preferred stock, shares	4,980	14,390	11,185
Stock options, shares	3,147	1,574	161
Diluted EPS, shares
Net income attributable to common stockholders plus assumed conversions, shares	81,698	56,645	42,666
Basic EPS, per share amount
Net income attributable to common stockholders, per share amount	$ 0.33	$ 0.14	$ 0.24
Diluted EPS, per share amount
Net income attributable to common stockholders plus assumed conversions, per share amount	$ 0.30	$ 0.12	$ 0.19