Loans - Pre-Modification and Post-Modification Outstanding Recorded Investments (Detail) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015 USD ($) Contract	Sep. 30, 2014 USD ($) Contract	Sep. 30, 2015 USD ($) Contract	Sep. 30, 2014 USD ($) Contract
Accounts, Notes, Loans and Financing Receivable
Number of Contracts | Contract	7	11	26	34
Pre-Modification Outstanding Recorded Investment	$ 7,584	$ 12,044	$ 20,196	$ 44,181
Post-Modification Outstanding Recorded Investment	$ 6,031	$ 8,884	$ 18,652	$ 37,179
Commercial and industrial
Accounts, Notes, Loans and Financing Receivable
Number of Contracts | Contract	2	1	12	9
Pre-Modification Outstanding Recorded Investment	$ 1,530	$ 3,159	$ 4,621	$ 11,340
Post-Modification Outstanding Recorded Investment	$ 1,530	$ 3,159	$ 4,081	$ 10,361
Commercial real estate
Accounts, Notes, Loans and Financing Receivable
Number of Contracts | Contract	0	4	4	12
Pre-Modification Outstanding Recorded Investment	$ 0	$ 6,111	$ 6,562	$ 22,282
Post-Modification Outstanding Recorded Investment	$ 0	$ 2,865	$ 6,444	$ 18,011
Construction
Accounts, Notes, Loans and Financing Receivable
Number of Contracts | Contract	2	1	3	3
Pre-Modification Outstanding Recorded Investment	$ 4,974	$ 403	$ 5,474	$ 5,731
Post-Modification Outstanding Recorded Investment	$ 3,451	$ 500	$ 4,635	$ 4,232
Total commercial real estate loans
Accounts, Notes, Loans and Financing Receivable
Number of Contracts | Contract	2	5	7	15
Pre-Modification Outstanding Recorded Investment	$ 4,974	$ 6,514	$ 12,036	$ 28,013
Post-Modification Outstanding Recorded Investment	$ 3,451	$ 3,365	$ 11,079	$ 22,243
Residential mortgage
Accounts, Notes, Loans and Financing Receivable
Number of Contracts | Contract	3	3	6	7
Pre-Modification Outstanding Recorded Investment	$ 1,080	$ 568	$ 2,458	$ 2,893
Post-Modification Outstanding Recorded Investment	$ 1,050	$ 557	$ 2,420	$ 2,640
Consumer
Accounts, Notes, Loans and Financing Receivable
Number of Contracts | Contract	0	2	1	3
Pre-Modification Outstanding Recorded Investment	$ 0	$ 1,803	$ 1,081	$ 1,935
Post-Modification Outstanding Recorded Investment	$ 0	$ 1,803	$ 1,072	$ 1,935