Earnings Per Share - Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Basic net income per share:
Net income (loss) available to common shareholders	$ (3,595)	$ 4,787
Weighted average common shares outstanding	45,030	46,551
Basic net income (loss) per share	$ (0.08)	$ 0.10
Diluted net income per share:
Net income (loss) available to common shareholders	$ (3,595)	$ 4,787
Weighted average common shares outstanding	45,030	46,551
Diluted stock options and non-vested restricted stock		657
Weighted average common shares outstanding for purposes of computing diluted net income (loss) per share	45,030	47,208
Diluted net income (loss) per share	$ (0.08)	$ 0.10