Dispositions and Held-for-Sale (Held-for-Sale) (Details) $ in Thousands	Dec. 31, 2017 USD ($)	Nov. 11, 2017 banking_branch	Dec. 31, 2016 USD ($)
Schedule Of Assets Held-For-Sale [Line Items]
Branch assets held-for-sale	$ 91,318		$ 0
Branch liability held-for-sale	605,111		$ 0
Loans held-for-sale
Schedule Of Assets Held-For-Sale [Line Items]
Branch assets held-for-sale	78,100
Premises and equipment held-for-sale
Schedule Of Assets Held-For-Sale [Line Items]
Branch assets held-for-sale	$ 8,000
California
Schedule Of Assets Held-For-Sale [Line Items]
Number of branches to be sold | banking_branch		8