Borrowings - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Assets Sold Under Agreements To Repurchase [Line Items]
Securities Sold Under Agreements to Repurchase	$ 600,590	$ 604,306
Long-term Repurchase Agreements with Government Entities
Assets Sold Under Agreements To Repurchase [Line Items]
Securities Sold Under Agreements to Repurchase	$ 500	2,100
Repurchase agreements, Weighted average interest rate (as a percent)	1.55%
Repurchase agreement counterparty, weighted average maturity of agreements	3 years 10 months 24 days
Long-term Repurchase Agreements with Private Institutions
Assets Sold Under Agreements To Repurchase [Line Items]
Securities Sold Under Agreements to Repurchase	$ 600,000	$ 600,000
Repurchase agreements, Weighted average interest rate (as a percent)	2.39%
Repurchase agreement counterparty, weighted average maturity of agreements	4 years
Repurchase Agreement Counterparty, Weighted Average Maturity of Agreements early termination	3 years 6 months
Long-term Repurchase Agreements with Private Institutions | Minimum [Member]
Assets Sold Under Agreements To Repurchase [Line Items]
Repurchase agreement remaining weighted average term range	2022
Long-term Repurchase Agreements with Private Institutions | Maximum
Assets Sold Under Agreements To Repurchase [Line Items]
Repurchase agreement remaining weighted average term range	2026