Repurchase Agreements (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase, Fair Value of Collateral	$ 685,900
Securities sold under customer repurchase agreements	663,575	$ 641,487
Available-for-sale Securities
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase, Fair Value of Collateral		689,300
Overnight and continuous
Assets Sold under Agreements to Repurchase [Line Items]
Securities sold under customer repurchase agreements	663,600	641,500
Overnight and continuous | US Government Agencies Debt Securities
Assets Sold under Agreements to Repurchase [Line Items]
Securities sold under customer repurchase agreements	571,600	432,800
Overnight and continuous | Commercial Mortgage Backed Securities
Assets Sold under Agreements to Repurchase [Line Items]
Securities sold under customer repurchase agreements	$ 92,000	$ 208,700