Securities (Scheduled Contractual Maturities of AFS Debt Securities) (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Amortized Cost
Due within one year	$ 561,935
Due after one year through five years	366,403
Due after five years through ten years	277,823
Due after ten years	2,617,553
Amortized Cost	3,823,714	$ 3,320,648
Fair Value
Due within one year	562,869
Due after one year through five years	371,895
Due after five years through ten years	289,730
Due after ten years	2,660,080
Total available-for-sale debt investment securities	3,884,574	3,317,214
Available for sale debt investment securities pledged as collateral, fair value	$ 745,163	$ 479,432

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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