Derivatives and Balance Sheet Offsetting - Collateral pledged table (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Balance Sheet Offsetting [Line Items]
Repurchase agreements, amounts offset in balance sheet	$ 0	$ 0
Repurchase agreements, net amount presented in statement of financial position	40,040	73,859
Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Securities	(40,040)	(73,859)
Securities sold under agreements to repurchase, amount not offset	0	0
Interest Rate Contracts [Member]
Balance Sheet Offsetting [Line Items]
Derivative Assets, Gross Amounts Offset in the Balance Sheets	0	0
Derivative Asset	29,139	46,184
Derivative, Collateral, Obligation to Return Cash	(370)	0
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	28,769	46,184
Derivative Liability, Gross Amounts Offset in Balance Sheets	0	0
Derivative Liability	29,139	46,637
Derivative, Collateral, Right to Reclaim Cash	26,670	46,637
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	2,469	0
Available-for-sale Securities [Member]
Balance Sheet Offsetting [Line Items]
Securities Sold under Agreements to Repurchase, Gross	40,040	73,859
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Balance Sheet Offsetting [Line Items]
Fair value of asset derivative instruments	29,139	46,184
Fair value of liability derivative instruments	$ 29,139	$ 46,637