Income Taxes - Summary of Reconciliation of Statutory Federal Tax and Effective Income Tax Rates (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reconciliation of Effective Income Tax Rates Continuing Operations
Federal income tax expense (1)	[1]	$ 23,865	$ 21,121	$ 19,205
State income taxes, net of federal benefit		3,062	2,946	3,105
ESOP dividend deduction		(263)	(267)	(256)
Other		241	145	31
Total Income Tax Expense		$ 26,905	$ 23,945	$ 22,085
Effective Income Tax Rate		39.54%	39.88%	40.25%

[1] Federal income taxes were recorded at 35% for each year represented.