Loans - Summary of the Activity in Loans Classified as TDRs (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Financing Receivable, Modifications [Line Items]
Beginning Balance	$ 3,284	$ 3,284
New TDR	2,149	10,271
Loss or Foreclosure	0	0
Transferred to Held For Sale		(6,987)
Loan Amortization	(1)
Removed from (Taken to) Non-accrual	0	0
Ending Balance	5,432	3,284
Non-Residential Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Beginning Balance	3,284	3,284
New TDR	2,149	10,271
Loss or Foreclosure	0	0
Transferred to Held For Sale		(6,987)
Loan Amortization	(1)
Removed from (Taken to) Non-accrual	0	0
Ending Balance	$ 5,432	$ 3,284