Fair Value - Summary of Carrying Value and Fair Value of Company's Financial Instruments (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013 Carrying Amount [Member]	Sep. 30, 2012 Carrying Amount [Member]	Sep. 30, 2013 Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]	Sep. 30, 2012 Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]	Sep. 30, 2013 Significant Other Observable Inputs (Level 2) [Member]	Sep. 30, 2012 Significant Other Observable Inputs (Level 2) [Member]	Sep. 30, 2013 Significant Unobservable Inputs (Level 3) [Member]	Sep. 30, 2012 Significant Unobservable Inputs (Level 3) [Member]
Financial Assets
Securities held to maturity		$ 14,542		$ 15,556		$ 0		$ 16,334		$ 0
Loans, net	1,242,496	1,203,977	1,223,712	1,156,979	0	0	0	0	1,245,373	1,178,911
Financial Liabilities
Deposit liabilities			1,698,910	1,679,466	0	0	0	0	1,700,289	1,681,968
Borrowings			50,000	50,000	0	0	54,223	55,947	0	0
Subordinated debt			$ 53,610	$ 53,610	$ 0	$ 0	$ 37,527	$ 32,166	$ 0	$ 0