Loans and Leases - Certain Information Relating to Commercial Loans (Detail) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Loans and Leases Receivable Disclosure [Line Items]
Commercial construction loans	$ 432,429	$ 352,322
Credit Concentration Risk [Member] | Commercial Construction Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Percent of total loans and leases	3.00%	2.90%
Loan Portfolio Diversification Risk [Member] | Commercial Real Estate Loans [Member] | Owner-Occupied [Member]
Loans and Leases Receivable Disclosure [Line Items]
Percent of total loans and leases	37.00%	38.10%
Loan Portfolio Diversification Risk [Member] | Commercial Real Estate Loans [Member] | Non-Owner-Occupied [Member]
Loans and Leases Receivable Disclosure [Line Items]
Percent of total loans and leases	63.00%	61.90%