Allowance for Loan Losses - Additional Information (Detail)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2015 USD ($) SecurityLoan	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($) SecurityLoan	Jun. 30, 2014 USD ($)	Dec. 31, 2014 USD ($) SecurityLoan
Receivables [Abstract]
Number of Loans under troubled debt restructurings | SecurityLoan	0		10		7
Recorded investment or loans under troubled debt restructurings	$ 1,500,000		$ 1,500,000		$ 600,000
Loans modified under troubled debt restructurings during previous twelve month period that subsequently defaulted	$ 0	$ 0	$ 0	$ 0