Servicing Assets - Summary of Key Assumptions in Fair Value Calculations (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019	Jun. 30, 2020	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Servicing Assets at Fair Value [Line Items]
Carrying amount	$ 6,166	$ 6,798
Residential Property
Servicing Assets at Fair Value [Line Items]
Carrying amount	117	171	$ 125	$ 189	$ 204	$ 244
Fair value	$ 140	$ 200
Discount rate	11.25%	11.25%
Prepayment speed	27.60%	26.60%
Weighted average remaining life	23 years 4 months 24 days	24 years 2 months 12 days
Underlying loans being serviced	$ 23,618	$ 32,428
SBA Property
Servicing Assets at Fair Value [Line Items]
Carrying amount	5,374	5,805	5,554	5,848	6,094	6,349
Fair value	$ 7,890	$ 6,693
Discount rate	13.25%	13.25%
Prepayment speed	10.78%	16.28%
Weighted average remaining life	21 years 1 month 6 days	21 years 3 months 18 days
Underlying loans being serviced	$ 384,356	$ 384,007
SBA Commercial Term
Servicing Assets at Fair Value [Line Items]
Carrying amount	675	822	$ 720	$ 862	$ 932	$ 1,073
Fair value	$ 942	$ 976
Discount rate	12.75%	12.75%
Prepayment speed	10.70%	16.03%
Weighted average remaining life	6 years 9 months 18 days	7 years
Underlying loans being serviced	$ 76,677	$ 82,181