Derivative Financial Instruments (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2021	Dec. 31, 2019
Securities Sold under Agreements to Repurchase [Abstract]
Gross Amounts Recognized	$ 209,038		$ 230,886
Gross Amounts Offset in the Statement of Financial Position	0		0
Net Amounts of Liabilities presented in the Statement of Financial Position	209,038		230,886
Financial Instruments	0		0
Fair Value Collateral Posted	209,038		230,886
Net Amount	0		0
Fair value of derivatives in a net liability position	45,200
Posted collateral	45,500
Interest rate swap
Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract]
Asset derivatives (other assets), fair value	33,999		11,055
Liability derivatives (other liabilities), fair value	44,240		14,747
Derivative Asset [Abstract]
Gross Amounts Offset in the Statement of Financial Position	0		0
Derivative financial instruments	33,999		11,055
Financial Instruments	2		56
Fair Value Collateral Posted	0		0
Net Amount	33,997		10,999
Derivative Liability [Abstract]
Gross Amounts Offset in the Statement of Financial Position	0		0
Net Amounts of Liabilities presented in the Statement of Financial Position	44,240		14,747
Financial Instruments	2		56
Fair Value Collateral Posted	44,063		14,573
Net Amount	175		118
Derivatives Designated as Hedging Instruments: | Other Assets [Member] | Interest rate swap
Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract]
Derivative Asset, Notional Amount	261,962		61,962
Asset derivatives (other assets), fair value	0		0
Derivatives Designated as Hedging Instruments: | Other Liabilities [Member] | Interest rate swap
Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract]
Liability derivatives (other liabilities), fair value	10,011		2,872
Derivatives not Designated as Hedging Instruments: | Other Assets [Member] | Interest rate swap
Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract]
Derivative Asset, Notional Amount	1,044,139		749,819
Asset derivatives (other assets), fair value	33,999		11,055
Derivatives not Designated as Hedging Instruments: | Other Liabilities [Member] | Interest rate swap
Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract]
Liability derivatives (other liabilities), fair value	$ 34,229		$ 11,875
Cash Flow Hedging | Subordinated Debt [Member]
Derivative [Line Items]
Derivative, Variable Interest Rate	2.62%
Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract]
Derivative Asset, Notional Amount	$ 62,000
Cash Flow Hedging | Federal Home Loan Bank Overnight Advances [Member]
Derivative [Line Items]
Derivative, fixed rate	1.12%
Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract]
Derivative Asset, Notional Amount	$ 100,000
Cash Flow Hedging | Federal Home Loan Bank 3 Month Advances [Member]
Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract]
Derivative Asset, Notional Amount	$ 100,000
Maximum | Cash Flow Hedging | Subordinated Debt [Member]
Derivative [Line Items]
Cash flow hedge term	6 years
Maximum | Cash Flow Hedging | Federal Home Loan Bank Overnight Advances [Member]
Derivative [Line Items]
Cash flow hedge term	3 years
Maximum | Cash Flow Hedging | Federal Home Loan Bank 3 Month Advances [Member]
Derivative [Line Items]
Cash flow hedge term	5 years
Scenario, Forecast | Cash Flow Hedging
Derivative [Line Items]
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income		$ 2,900