Securities, HTM Debt Securities, Contractual Maturities (Details) $ in Thousands	Jun. 30, 2021 USD ($) Issuer	Dec. 31, 2020 USD ($) Issuer
Held-to-maturity Securities, Debt Maturities, Amortized Cost [Abstract]
Within one year	$ 51,610
From one to five years	54,875
From five to ten years	227,013
After ten years	288,853
Amortized cost	622,351	$ 616,560
Held-to-maturity Securities, Debt Maturities, Estimated Fair Value [Abstract]
Within one year	51,659
From one to five years	56,215
From five to ten years	229,266
After ten years	295,814
Fair value	$ 632,954	$ 636,827
Number of issuers whose holdings exceeded 10% of consolidated stockholders' equity, excluding U.S. Government securities and Government-sponsored enterprises securities | Issuer	0	0