Earnings Per Share - Computation of Basic and Diluted Earnings 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 from continuing operations attributable to common shareholders	$ 16,673	$ 14,113
Denominator:
Denominator for basic earnings per share - weighted average shares	32,383,996	30,488,853
Effect of Dilutive Securities:
Stock options and non-vested stock	154,000	165,000
Denominator for diluted earnings per share - adjusted weighted average shares and assumed conversion	32,538,429	30,654,495
Basic earnings per common share from continuing operations attributable to common shareholders	$ 0.51	$ 0.46
Basic earnings per common share attributable to common shareholders	$ 0.51	$ 0.47
Diluted earnings per common share from continuing operations attributable to common shareholders	$ 0.51	$ 0.46
Diluted earnings per common share attributable to common shareholders	$ 0.51	$ 0.47