Indemnifications and Guarantees - Additional Information (Detail) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2014 Transactions Financial_Institution	Mar. 31, 2013	Dec. 31, 2013 Transactions
Guarantor Obligations [Line Items]
Provision for losses at the time of sale	$ 2,630,000	$ 2,231,000
Number of unrelated financial institutions	3
Derivative transaction held for guarantee	103		101
Aggregate notional amount	450,100,000		423,900,000
Notional amount maturity period	1 year
Notional amount maturity period	11 years
Aggregate market value of swaps to customers	18,800,000		17,800,000
Reserve for swap guarantees	70,000
Secondary Market Loan Sales [Member]
Guarantor Obligations [Line Items]
Provision for losses at the time of sale	0
Repurchase of the loans	$ 0
Minimum [Member]
Guarantor Obligations [Line Items]
Term period of loan	15 years
Maximum [Member]
Guarantor Obligations [Line Items]
Term period of loan	30 years