Securities (Schedule of Contractual Maturities of Investment Securities Available for Sale) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Abstract]
Due within one year, Amortized Cost	$ 34,642
Due after one year through five years, Amortized Cost	361,355
Due after five years through ten years, Amortized Cost	1,892,926
Due after ten years, Amortized Cost	1,117,569
Debt securities available-for-sale, amortized cost	3,406,492	$ 3,703,096
Due within one year, Fair Value	34,693
Due after one year through five years, Fair Value	372,492
Due after five years through ten years, Fair Value	1,996,364
Due after ten years, Fair Value	1,149,579
Debt securities available for sale at fair value	$ 3,553,128	$ 3,746,142

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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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in sixth fiscal year through tenth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in sixth through tenth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in second through fifth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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