Loans Receivable and Allowance for Loan Losses - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013 Borrowers SecurityLoan	Dec. 31, 2012 SecurityLoan Borrowers	Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortization of interest income	$ 1,286,000	$ 1,694,000	$ 1,902,000
Principal amount of nonaccrual loans	76,680,000	98,990,000
Increase in interest income	1,913,000	3,022,000	3,496,000
Impaired loan defined floor limit	1,000,000
Impaired loans number	152	108
Impaired loans	106,370,000	109,630,000
Number of troubled debt restructurings		94
Number of borrowers	110	70
Loans and leases receivable, impaired, nonperforming, accrual of interest		84,000,000
Loans charged off	14,406,000	23,907,000	25,053,000
Allowances for loan losses	10,217,000	7,211,000
Weighted average modified interest rate	4.08%	4.81%
Yield percentage rate	5.75%	5.89%
Average balances of impaired loans	111,008,000	115,611,000	108,654,000
Loan commitments	657,563,000	601,914,000
Undisbursed home equity and personal credit lines	252,522,000	267,078,000
Impaired Loans - Trouble Debt Restructurings [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans number	142
Impaired loans	89,400,000
Number of troubled debt restructurings	115	80
Loans and leases receivable, impaired, nonperforming, accrual of interest	58,200,000	58,400,000
Allowances for loan losses	1,000,000	2,000,000
With Related Allowance For Loan Losses [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Allowances for loan losses	10,217,000	7,211,000
No Allowance for Loan Losses Required [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired financing receivable with no related allowance	21,958,000	34,484,000
Residential Commercial And Commercial Mortgage Loan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans number	152	108
Impaired loans	106,400,000	109,600,000
Residential Commercial And Commercial Mortgage Loan [Member] | Non-Accrual [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans number	37	14
Impaired loans	$ 48,204,000	$ 25,674,000