Disclosures about Fair Value of Assets and Liabilities - Realized Gains and Losses included in Net Income for Periods in Consolidated Statements of Income (Details) - Non-interest Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Included in net income	$ 994	$ (429)	$ 1,358	$ (97)
Hedged loans
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Included in net income	1,944	(6,091)	(27,548)	(17,671)
Interest rate swap agreements liability
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Included in net income	(1,944)	6,091	27,548	17,671
Derivative loan commitments
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Included in net income	$ 994	$ (429)	$ 1,358	$ (97)