Indemnification Asset - Summary of Activity in Balance of Indemnification Asset (Liability) (Detail) - USD ($) $ in Thousands		3 Months Ended	9 Months Ended
	May 09, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
FDIC Indemnification Asset [Roll Forward]
Beginning (payable) receivable balance		$ (662)	$ (744)	$ (521)
Effect of actual covered losses and change in estimated future covered losses		17	(224)	(245)
Reimbursable expenses (revenue), net			256	(4)
Payments made (received)	$ (184)	107		232
Gain on termination of loss share agreement	$ (712)		712
Ending (payable) receivable balance		(538)		(538)
Amount of indemnification asset recorded in other assets				95
Amount of indemnification liability recorded in other liabilities				(633)
Ending balance		$ (662)	$ (744)	$ (538)