Investment Securities - Contractual Maturities of Debt Securities Held to Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Amortized Cost
Due in one year	$ 94,100
Due after one year through five years	169,651
Due after five years through ten years	213,801
Due after ten years	223,331
Residential mortgage-backed securities	1,616,150
Amortized Cost	2,317,033	$ 2,336,095
Fair Value
Due in one year	95,561
Due after one year through five years	176,406
Due after five years through ten years	224,212
Due after ten years	219,356
Residential mortgage-backed securities	1,667,403
Total investment securities held to maturity	$ 2,382,938	$ 2,358,720

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

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