Derivatives - Additional Information (Detail) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019 USD ($) Derivatives	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) Derivatives	Jun. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)
Risk participation Agreements [Line Items]
Derivative, Net Hedge Ineffectiveness Gain (Loss)	$ 0	$ (653)
Derivative, Gain (Loss) on Derivative, Net	$ (17)	0	$ (43)	$ 789
Risk Participation Agreements Purchased [Domain]
Risk participation Agreements [Line Items]
Number of interest rate swaps | Derivatives	35		35
Risk Participation Agreements Sold [Domain]
Risk participation Agreements [Line Items]
Number of interest rate swaps | Derivatives	11		11
Forward Contracts [Member]
Risk participation Agreements [Line Items]
Derivative, Net Hedge Ineffectiveness Gain (Loss)	$ 0	33	$ 0	(29)
Derivative Liability, Cost Basis, Gross Asset	17,800		17,800		$ 6,900
Derivative Liability, Fair Value, Gross Asset	19,200		19,200		7,600
Derivative Liability, Notional Amount, Gross Asset	28,000		28,000		9,900
Derivative, Gain (Loss) on Derivative, Net	(15)	0	(79)	0
Forward Contracts [Member] | Designated as Hedging Instrument [Member]
Risk participation Agreements [Line Items]
Derivative, Fair Value, Net	249		249		170
Derivative, Notional Amount	33,000		33,000		15,000
Interest Rate Contract [Member]
Risk participation Agreements [Line Items]
Derivative, Net Hedge Ineffectiveness Gain (Loss)			0	(653)
Foreign Exchange [Member]
Risk participation Agreements [Line Items]
Derivative, Net Hedge Ineffectiveness Gain (Loss)	(1)	11	1	8
Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member]
Risk participation Agreements [Line Items]
Derivative, Fair Value, Net	16		16		6
Derivative, Notional Amount	4,601		4,601		1,927
Derivative Liability, Cost Basis, Gross Asset	4,600		4,600		1,900
Derivative Liability, Fair Value, Gross Asset	4,600		4,600		1,900
Interest Rate Swap [Member]
Risk participation Agreements [Line Items]
Derivative Instruments Designated As Hedging Instruments Interest Income	0	(150)	(118)	(231)
Derivative, Net Hedge Ineffectiveness Gain (Loss)	0	$ 10	7	$ 10
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member]
Risk participation Agreements [Line Items]
Derivative, Fair Value, Net	0		0		133
Derivative, Notional Amount	$ 0		$ 0		$ 65,000