Allowance for Loan Losses - Additional Information (Detail) (USD $)	9 Months Ended								9 Months Ended
	Sep. 30, 2014 Category	Sep. 30, 2014 Originated loans [Member]	Dec. 31, 2013 Originated loans [Member]	Sep. 30, 2013 Originated loans [Member]	Sep. 30, 2014 PNCI loans [Member]	Dec. 31, 2013 PNCI loans [Member]	Sep. 30, 2013 PNCI loans [Member]	Sep. 30, 2013 PCI loans [Member]	Sep. 30, 2014 Minimum [Member]	Sep. 30, 2014 Maximum [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Period of collateral payment of loan									3 months	12 months
Number of categories occupied under commercial real estate loans	2
Impaired TDRs Loans		$ 53,102,000	$ 56,739,000	$ 54,551,000	$ 1,344,000	$ 901,000	$ 928,000	$ 87,000
Additional funds in TDRs		29,000	25,000	50,000
Obligations to lend additional funds on TDRs					$ 0	$ 0	$ 0