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Derivative Financial Instruments - Interest Swap Derivatives (Details) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended		6 Months Ended	9 Months Ended		12 Months Ended
	Mar. 31, 2021	Jun. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Jun. 30, 2021	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Value			$ 260,000			$ 260,000		$ 405,700
Fair Value			(18,710)			(18,710)		(30,390)
Interest expense			12,115	$ 16,518		36,640	$ 57,540
Payments for swap termination payments		$ 46,100
Interest rate swaps | Derivatives designated as hedging instruments
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Value			50,000			$ 50,000		$ 88,200
Weighted Average Remaining Maturity (years)						3 years 1 month 6 days		3 years 1 month 6 days
Fair Value			$ (2,608)			$ (2,608)		$ (6,072)
Weighted-Average Rate			2.33%			2.33%		2.54%
Cash collateral received								$ 19,300
Cash collateral pledged								30,600
Loans | Interest rate swaps | Derivatives designated as hedging instruments
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Weighted Average Remaining Maturity (years)						12 years 4 months 9 days
Securities available-for-sale | Derivatives designated as hedging instruments
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Fair value hedging adjustment					$ 6,064	$ 2,606
Securities available-for-sale | Interest rate swaps | Derivatives designated as hedging instruments
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Value			$ 50,000			$ 50,000		$ 88,200
Weighted Average Remaining Maturity (years)						3 years 1 month 6 days		3 years 1 month 6 days
Fair Value			$ (2,608)			$ (2,608)		$ (6,072)
Weighted-Average Rate			2.33%			2.33%		2.54%
Payments for swap termination payments	$ 1,900
Derivative Instrument, Notional Amount, Terminated	$ 38,200
3-month LIBOR | Interest rate swaps | Derivatives designated as hedging instruments
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Value			$ 110,000			$ 110,000		$ 110,000
Weighted Average Remaining Maturity (years)						5 years 3 months 18 days		6 years 1 month 6 days
Fair Value			$ (10,563)			$ (10,563)		$ (15,727)
Derivative, variable interest rate			2.88%			2.88%		2.88%
1-month LIBOR | Interest rate swaps | Derivatives designated as hedging instruments
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Value			$ 100,000			$ 100,000		$ 100,000
Weighted Average Remaining Maturity (years)						2 years 2 months 12 days		3 years
Fair Value			$ (5,449)			$ (5,449)		$ (7,951)
Derivative, variable interest rate			2.88%			2.88%		2.88%

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Fair value of the assets less the liabilities of a derivative or group of derivatives.

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Variable interest rate in effect as of the balance sheet date related to the interest rate derivative.

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