Estimated Fair Values (Narrative) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers Into Level 3	$ 0
Gains (Losses) from fair value changes on originated loans held for sale	249	$ (455)
Fair Value, Measurements, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liability measured at fair value on nonrecurring basis	$ 0		$ 0
Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers Into Level 3		59,700
Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers Into Level 3		$ 5,600
Discount Rate | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, measurement input	0.06
OREO, measurement input	0.06
Discount Rate | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, measurement input	0.11
OREO, measurement input	0.11
Effective Interest Rate | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, measurement input	0.02
Effective Interest Rate | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, measurement input	0.18