Repurchase Agreements (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase, Fair Value of Collateral	$ 748,100
Securities sold under customer repurchase agreements	693,889	$ 442,956
Available-for-sale Securities
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase, Fair Value of Collateral		477,600
Overnight and continuous
Assets Sold under Agreements to Repurchase [Line Items]
Securities sold under customer repurchase agreements	693,900
Overnight and continuous | US Government Agencies Debt Securities
Assets Sold under Agreements to Repurchase [Line Items]
Securities sold under customer repurchase agreements	444,000	$ 443,000
Overnight and continuous | Commercial Mortgage Backed Securities
Assets Sold under Agreements to Repurchase [Line Items]
Securities sold under customer repurchase agreements	$ 249,900