Securities, HTM Debt Securities, Contractual Maturities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Held-to-maturity Securities, Debt Maturities, Amortized Cost [Abstract]
Within one year	$ 60,959
From one to five years	67,594
From five to ten years	190,717
After ten years	425,331
Amortized cost	744,601	$ 783,599
Held-to-maturity Securities, Debt Maturities, Estimated Fair Value [Abstract]
Within one year	60,959
From one to five years	68,031
From five to ten years	193,697
After ten years	432,308
Fair value	$ 754,995	$ 778,675

Amount of investment in debt security measured at amortized cost (held-to-maturity).

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