Earnings Per Share - Reconciles Numerators and Denominators of Basic Earnings Per Share with Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Numerator for Earnings per Share-Basic:
Net income	$ 16,093	$ 12,835
Less: Income allocated to participating shares	41	46
Net Income Allocated to Shareholders	16,052	12,789
Numerator for Earnings per Share-Diluted:
Net income	16,093	12,835
Net Income Available to Shareholders	$ 16,093	$ 12,835
Denominators:
Weighted Average Shares Outstanding-Basic	34,661,016	31,232,075
Add: Potentially dilutive shares	78,498	28,873
Denominator for Treasury Stock Method-Diluted (in shares)	34,739,514	31,260,948
Weighted Average Shares Outstanding-Basic	34,661,016	31,232,075
Add: Average participating shares outstanding	88,265	111,774
Denominator for Two-Class Method-Diluted (in shares)	34,749,281	31,343,849
Earnings per share—basic (in dollars per share)	$ 0.46	$ 0.41
Earnings per share—diluted (in dollars per share)	0.46	0.41
Anti-dilutive warrants - exercise price (in dollars per share)	$ 31.53	$ 31,530.00
Warrants
Denominators:
Anti-dilutive excluded from potentially dilutive shares	517,012	517,012
Stock Options
Denominators:
Anti-dilutive excluded from potentially dilutive shares	0	155,500
Restricted Stock
Denominators:
Anti-dilutive excluded from potentially dilutive shares	81,840	82,901