Commitments and Contingencies (Off-Balance Sheet Financial Instruments) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Commitments to extend credit [Member]
Loss Contingencies [Line Items]
Contract amounts	$ 7,212,886	$ 6,689,033
Letters of Credit [Member]
Loss Contingencies [Line Items]
Contract amounts	$ 353,490	$ 348,377

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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