Securities (Scheduled Contractual Maturities of Investment Securities) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Amortized Cost
Due within one year	$ 563,394
Due after one year through five years	585,603
Due after five years through ten years	202,347
Due after ten years	1,324,490
Total available-for-sale debt investment securities, Amortized Cost	2,675,834	$ 2,806,900
Fair Value
Due within one year	546,641
Due after one year through five years	576,863
Due after five years through ten years	202,118
Due after ten years	1,314,536
Total available-for-sale debt investment securities	2,640,158	2,741,847
Fair values of available-for-sale debt investment securities pledged	$ 449,000	$ 435,800

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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