Loans - Troubled Debt Restructurings (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Financing Receivable, Modifications [Line Items]
Balance at time of restructuring	$ 6,874	$ 6,303
Balance at period end	6,741	5,069
Commercial and industrial, Other commercial [Member]
Financing Receivable, Modifications [Line Items]
Balance at time of restructuring	3,752	2,138
Balance at period end	3,672	1,343
Commercial real estate, Buildings, land and other [Member]
Financing Receivable, Modifications [Line Items]
Balance at time of restructuring	3,122	4,165
Balance at period end	$ 3,069	$ 3,726