Commitments and Contingencies (Off-Balance Sheet Financial Instruments) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Commitments to Extend Credit [Member]
Loss Contingencies [Line Items]
Contract amounts	$ 6,689,033	$ 5,878,290
Letters of Credit [Member]
Loss Contingencies [Line Items]
Contract amounts	$ 348,377	$ 338,014

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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