Fair Value Measurements (Financial Assets Measured at Fair Value on Nonrecurring Basis) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral-dependent impaired loans	$ 206,110	$ 184,205
Other real estate owned	5,926	6,928
Total nonrecurring fair value measurements	212,036	191,133
Nonrecurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral-dependent impaired loans
Other real estate owned
Total nonrecurring fair value measurements
Nonrecurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral-dependent impaired loans	206,110	184,205
Total nonrecurring fair value measurements	206,110	184,205
Nonrecurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned	5,926	6,928
Total nonrecurring fair value measurements	$ 5,926	$ 6,928