Variable Interest Entities - Summary of Activity in Allowance for Loan Losses (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended		12 Months Ended
	Jun. 30, 2020	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Residential Mortgage Backed Securities
Variable Interest Entity [Line Items]
Balance at beginning of period	$ 56
Balance at end of period	56	$ 56
Residential Mortgage Backed Securities | Accounting Standards Update 2016-13 | Adjustment
Variable Interest Entity [Line Items]
Balance at end of period	30	30
Variable Interest Entities Primary Beneficiary
Variable Interest Entity [Line Items]
Balance at beginning of period		175,000
Balance at end of period				$ 175,000
Variable Interest Entities Primary Beneficiary | Residential Mortgage Backed Securities
Variable Interest Entity [Line Items]
Balance at beginning of period	167	175
Provision for Loan and Lease Losses, net	564	594
Charge-offs, net	(584)	(622)	$ (11)	(11)
Balance at end of period	$ 147	$ 147	$ 175	$ 175