Investment Securities - Contractual Maturities of Available for Sale (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Amortized Cost
Due in one year	$ 9,121
Due after one year through five years	125,530
Due after five years through ten years	66,064
Due after ten years	103,967
Residential mortgage-backed securities	1,373,033
Amortized Cost	1,677,715	$ 1,796,404
Fair Value
Due in one year	9,117
Due after one year through five years	125,671
Due after five years through ten years	67,046
Due after ten years	104,537
Residential mortgage-backed securities	1,372,979
Total investment securities available for sale	$ 1,679,350	$ 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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