Balance Sheet Offsetting - Fair Value of the Related Collateral Pledged Against Repurchase Agreements (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	$ 450,490	$ 600,590
Debt Securities Issued by States and Political Subdivisions
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	490	590
Residential - Government Agencies
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	57,063	103,809
Residential - U.S. Government-Sponsored Enterprises
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	392,937	496,191
Maturity Up To 90 Days
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	0	100
Maturity Up To 90 Days | Debt Securities Issued by States and Political Subdivisions
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	0	100
Maturity Up To 90 Days | Residential - Government Agencies
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	0	0
Maturity Up To 90 Days | Residential - U.S. Government-Sponsored Enterprises
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	0	0
Maturity 91 To 365 Days
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	0	0
Maturity 91 To 365 Days | Debt Securities Issued by States and Political Subdivisions
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	0	0
Maturity 91 To 365 Days | Residential - Government Agencies
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	0	0
Maturity 91 To 365 Days | Residential - U.S. Government-Sponsored Enterprises
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	0	0
Maturity 1 To 3 Years
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	275,000	25,000
Maturity 1 To 3 Years | Debt Securities Issued by States and Political Subdivisions
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	0	0
Maturity 1 To 3 Years | Residential - Government Agencies
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	43,461	20,210
Maturity 1 To 3 Years | Residential - U.S. Government-Sponsored Enterprises
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	231,539	4,790
Maturity After 3 Years
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	175,490	575,490
Maturity After 3 Years | Debt Securities Issued by States and Political Subdivisions
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	490	490
Maturity After 3 Years | Residential - Government Agencies
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	13,602	83,599
Maturity After 3 Years | Residential - U.S. Government-Sponsored Enterprises
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	$ 161,398	$ 491,401