Derivative Instruments and Hedging Activities - Value of Derivative Assets and Derivative Liabilities (Details) - Not Designated as Hedging Instruments - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Other Assets
Derivatives not Designated as Hedging Instruments
Fair value	$ 90,163	$ 25,647
Other Assets \| Interest rate swap contracts—commercial loans
Derivatives not Designated as Hedging Instruments
Fair value	90,163	25,647
Notional amount	943,369	740,762
Collateral posted	0	0
Other Assets \| Interest rate lock commitments—mortgage loans
Derivatives not Designated as Hedging Instruments
Fair value	3,198	321
Notional amount	51,985	9,829
Other Assets \| Forward sale contracts—mortgage loans
Derivatives not Designated as Hedging Instruments
Fair value	0	1
Notional amount	0	12,750
Other Liabilities
Derivatives not Designated as Hedging Instruments
Fair value	90,616	25,615
Other Liabilities \| Interest rate swap contracts—commercial loans
Derivatives not Designated as Hedging Instruments
Fair value	90,616	25,615
Notional amount	943,369	740,762
Collateral posted	90,820	26,127
Other Liabilities \| Interest rate lock commitments—mortgage loans
Derivatives not Designated as Hedging Instruments
Fair value	0	0
Notional amount	0	0
Other Liabilities \| Forward sale contracts—mortgage loans
Derivatives not Designated as Hedging Instruments
Fair value	450	0
Notional amount	$ 51,871	$ 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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Nominal or face amount used to calculate payments on the derivative liability.

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