Borrowings and Borrowing Capacity - Summary of FHLB Advances and Weighted Average Interest Rates by Contractual Maturity (Details) $ in Thousands	Sep. 30, 2020 USD ($)
Debt Disclosure [Abstract]
2020, Balance Outstanding, Fixed Rate	$ 405,000
2027, Balance Outstanding, Fixed Rate	0
Total Balance Outstanding, Fixed Rate	$ 405,000
2020, Fixed Weighted Average Interest Rate	0.13%
2027, Fixed Weighted Average Interest Rate	0.00%
Total Fixed Weighted Average Interest Rate	0.13%
2020, Balance Outstanding, Variable Rate	$ 0
2027, Balance Outstanding, Variable Rate	30,000
Total Balance Outstanding, Variable Rate	$ 30,000
2020, Variable Weighted Average Interest Rate	0.00%
2027, Variable Weighted Average Interest Rate	0.33%
Total Variable Weighted Average Interest Rate	0.33%