Investment Securities (Schedule of Maturities of Investment Securities Available for Sale) (Details) $ in Thousands	Jun. 30, 2020 USD ($)
Investments, Debt and Equity Securities [Abstract]
Due in one year or less, Amortized Cost	$ 908,180
Due after one year through five years, Amortized Cost	4,875,569
Due after five years through ten years, Amortized Cost	2,304,114
Due after ten years, Amortized Cost	509,718
Amortized Cost	8,597,581
Due in one year or less, Fair Value	914,970
Due after one year through five years, Fair Value	4,830,499
Due after five years through ten years, Fair Value	2,332,121
Due after ten years, Fair Value	517,341
Fair Value	$ 8,594,931

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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