Investment Securities and Equity Securities with Readily Determinable Fair Values (Fair Value and Gross Unrealized Loss) (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Available for sale:
Fair value, less than 12 months	$ 589,056	$ 523,797
Unrealized losses, less than 12 Months	(3,630)	(2,274)
Fair value, 12 months or more		1,448,109
Unrealized losses, 12 Months or More		(14,340)
Fair value, Total	589,056	1,971,906
Unrealized losses, Total	(3,630)	(16,614)
Residential mortgage-backed securities
Available for sale:
Fair value, less than 12 months	588,298	523,031
Unrealized losses, less than 12 Months	(3,617)	(2,269)
Fair value, 12 months or more		1,448,109
Unrealized losses, 12 Months or More		(14,340)
Fair value, Total	588,298	1,971,140
Unrealized losses, Total	(3,617)	(16,609)
Obligations of states and political subdivisions
Available for sale:
Fair value, less than 12 months	758	766
Unrealized losses, less than 12 Months	(13)	(5)
Fair value, Total	758	766
Unrealized losses, Total	$ (13)	$ (5)

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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