Securities, HTM Debt Securities, Contractual Maturities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Held-to-maturity Securities, Debt Maturities, Amortized Cost [Abstract]
Within one year	$ 27,010
From one to five years	53,895
From five to ten years	171,942
After ten years	377,227
Amortized cost	630,074	$ 783,599
Held-to-maturity Securities, Debt Maturities, Estimated Fair Value [Abstract]
Within one year	27,010
From one to five years	54,358
From five to ten years	175,630
After ten years	384,264
Fair value	$ 641,262	$ 778,675