Loans and Allowance for Loan Losses - Analysis of Changes in Loans to Officers, Directors, Principal Shareholders, or Associates of Such Persons (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014
Receivables [Abstract]
Beginning Balance	$ 47,299
Additional Loans	132,118
Payments	124,620
Ending Balance	$ 54,797