Investment Securities - Contractual Maturities of Debt Securities Held to Maturity (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Amortized Cost
Due in one year	$ 96,230
Due after one year through five years	170,615
Due after five years through ten years	216,437
Due after ten years	232,694
Residential mortgage-backed securities	1,620,119
Amortized Cost	2,336,095	$ 2,068,246
Fair Value
Due in one year	97,223
Due after one year through five years	176,005
Due after five years through ten years	226,086
Due after ten years	229,834
Residential mortgage-backed securities	1,629,572
Total investment securities held to maturity	$ 2,358,720	$ 2,034,943

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

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