Investment Securities - Contractual Maturities of Available for Sale (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Amortized Cost
Due in one year	$ 19,554
Due after one year through five years	110,337
Due after five years through ten years	90,297
Due after ten years	89,785
Residential mortgage-backed securities	1,248,814
Total investment securities available for sale	1,558,787	$ 1,796,404
Fair Value
Due in one year	19,611
Due after one year through five years	110,801
Due after five years through ten years	91,232
Due after ten years	90,371
Residential mortgage-backed securities	1,254,786
Total investment securities available for sale	$ 1,566,801	$ 1,749,544

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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