Fair Value (Financial Assets Measured at Fair Value on Nonrecurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral-dependent impaired loans	$ 129,230	$ 169,888
Other real estate owned	6,810	13,968
Total nonrecurring fair value measurements	136,040	183,856
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	129,230	169,888
Total nonrecurring fair value measurements	129,230	169,888
Nonrecurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned	6,810	13,968
Total nonrecurring fair value measurements	$ 6,810	$ 13,968