Derivative Instruments and Hedging Activities - Value of Derivative Assets and Derivative Liabilities (Details) - Not Designated as Hedging Instruments - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Other Assets
Derivatives not Designated as Hedging Instruments
Fair value, Derivatives (included in Other Assets)	$ 25,647	$ 5,504
Other Assets \| Interest Rate Swap Contracts—Commercial Loans
Derivatives not Designated as Hedging Instruments
Fair value, Derivatives (included in Other Assets)	25,647	5,504
Notional amount, Derivatives (included in Other Assets)	740,762	325,750
Collateral posted, Derivatives (included in Other Assets)	0	160
Other Assets \| Interest Rate Lock Commitments—Mortgage Loans
Derivatives not Designated as Hedging Instruments
Fair value, Derivatives (included in Other Assets)	321	251
Notional amount, Derivatives (included in Other Assets)	9,829	6,054
Other Assets \| Forward Sale Contracts—Mortgage Loans
Derivatives not Designated as Hedging Instruments
Fair value, Derivatives (included in Other Assets)	1	55
Notional amount, Derivatives (included in Other Assets)	12,750	6,000
Other Liabilities
Derivatives not Designated as Hedging Instruments
Fair value, Derivatives (included in Other Liabilities)	25,615	5,340
Other Liabilities \| Interest Rate Swap Contracts—Commercial Loans
Derivatives not Designated as Hedging Instruments
Fair value, Derivatives (included in Other Liabilities)	25,615	5,340
Notional amount, Derivatives (included in Other Liabilities)	740,762	325,750
Collateral posted, Derivatives (included in Other Liabilities)	26,127	0
Other Liabilities \| Interest Rate Lock Commitments—Mortgage Loans
Derivatives not Designated as Hedging Instruments
Fair value, Derivatives (included in Other Liabilities)	0	0
Notional amount, Derivatives (included in Other Liabilities)	0	0
Other Liabilities \| Forward Sale Contracts—Mortgage Loans
Derivatives not Designated as Hedging Instruments
Fair value, Derivatives (included in Other Liabilities)	0	0
Notional amount, Derivatives (included in Other Liabilities)	$ 0	$ 0

Fair value of securities received as collateral against derivative assets.

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Nominal or face amount used to calculate payments on the derivative asset.

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Fair value of securities pledged as collateral against derivative liabilities.

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Nominal or face amount used to calculate payments on the derivative liability.

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