Loans - Average Recorded Investment and Interest Income Recognized on Impaired Loans (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	$ 192,549	$ 217,307
Interest Income Recognized	1,431	1,391
Commercial Real Estate Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	117,180	132,559
Interest Income Recognized	789	820
Consumer Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	1,076	1,214
Interest Income Recognized	13	12
Commercial and Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	46,784	55,266
Interest Income Recognized	369	376
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	97,542	113,401
Interest Income Recognized	645	751
Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	19,638	19,158
Interest Income Recognized	144	69
Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	27,509	28,268
Interest Income Recognized	260	183
Home Equity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	1,076	1,214
Interest Income Recognized	$ 13	$ 12