Balance Sheet Offsetting - Schedule of Assets and Liabilities Subject to an Enforceable Master Netting Arrangement or Repurchase Agreements (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Liabilities:
Repurchase Agreements, Gross Amounts of Recognized Liabilities	$ 600,490	$ 600,590
Repurchase Agreements, Gross Amounts Offset in the Statements of Condition	0	0
Repurchase Agreements, Net Amounts of Liabilities Presented in the Statements of Condition	600,490	600,590
Securities Sold under Agreements to Repurchase, Net Amount Offset Against Collateral	0	0
Repurchase Agreements, Fair Value of Collateral Pledged	600,490	600,590
Private Institutions
Liabilities:
Repurchase Agreements, Gross Amounts of Recognized Liabilities	600,000	600,000
Repurchase Agreements, Gross Amounts Offset in the Statements of Condition	0	0
Repurchase Agreements, Net Amounts of Liabilities Presented in the Statements of Condition	600,000	600,000
Securities Sold under Agreements to Repurchase, Net Amount Offset Against Collateral	0	0
Repurchase Agreements, Fair Value of Collateral Pledged	600,000	600,000
Government Entities
Liabilities:
Repurchase Agreements, Gross Amounts of Recognized Liabilities	490	590
Repurchase Agreements, Gross Amounts Offset in the Statements of Condition	0	0
Repurchase Agreements, Net Amounts of Liabilities Presented in the Statements of Condition	490	590
Securities Sold under Agreements to Repurchase, Net Amount Offset Against Collateral	0	0
Repurchase Agreements, Fair Value of Collateral Pledged	490	590
Interest Rate Swap Agreements | Institutional Counterparties
Assets:
Gross Amounts of Recognized Assets		5
Gross Amounts Offset in the Statements of Condition		0
Net Amounts of Assets Presented in the Statements of Condition		5
Netting Adjustments per Master Netting Arrangements		5
Gross Amounts Not Offset in the Statements of Condition - FV of collateral pledged		0
Derivative Assets, Net Amount		0
Liabilities:
Gross Amounts of Recognized Liabilities	11,627	17,202
Gross Amounts Offset in the Statements of Condition	0	0
Net Amounts of Liabilities Presented in the Statements of Condition	11,627	17,202
Derivative Liability, Netting Adjustments per Master Netting Arrangements	0	5
Derivative, Collateral, Right to Reclaim Securities	7,071	7,911
Derivative Liabilities, Net Amount	$ 4,556	$ 9,286