Securities (Scheduled Contractual Maturities of Investment Securities) (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Amortized Cost
Due within one year	$ 586,072
Due after one year through five years	432,912
Due after five years through ten years	193,117
Due after ten years	1,373,404
Total available-for-sale debt investment securities, Amortized Cost	2,585,505	$ 2,806,900
Fair Value
Due within one year	581,305
Due after one year through five years	430,486
Due after five years through ten years	196,457
Due after ten years	1,384,665
Total available-for-sale debt investment securities	2,592,913	2,741,847
Available for sale debt investment securities Pledged as Collateral, at Fair Value	$ 493,693	$ 435,833

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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