Securities, HTM Debt Securities, Contractual Maturities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Held-to-maturity Securities, Debt Maturities, Amortized Cost [Abstract]
Within one year	$ 85,778
From one to five years	62,441
From five to ten years	213,184
After ten years	422,196
Amortized cost	783,599	$ 484,073
Held-to-maturity Securities, Debt Maturities, Estimated Fair Value [Abstract]
Within one year	85,778
From one to five years	62,558
From five to ten years	210,480
After ten years	419,859
Fair value	$ 778,675	$ 481,871

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

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