Derivatives (Offsetting Derivative Assets and Liabilities Subject to Master Netting Arrangements) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Derivatives [Abstract]
Gross Amounts Recognized, Derivative Assets	$ 5,271	$ 4,788
Gross Amounts Offset in the Statement of Income, Derivative Assets	(3,942)
Net Amounts Presented in the Statement of Income, Derivative Assets	1,329	4,788
Gross Amounts Not Offset in the Statement of Income - Financial Instruments, Derivative Assets	1,329	4,788
Gross Amounts Not offset in the Statement of Income -Cash Collateral, Derivative Assets
Net Amounts Presented in the Statement of Income, Derivative Assets
Gross Amounts Recognized, Derivative Liabilities	21,889	26,846
Gross Amounts Offset in the Statement of Income, Derivative Liabilities	(16,322)
Net Amounts Presented in the Statement of Income, Derivative Liabilities	5,567	26,846
Gross Amounts Not Offset in the Statement of Income - Financial Instruments, Derivative Liabilities	1,329	4,788
Gross Amounts Not offset in the Statement of Income -Cash Collateral, Derivative Liabilities	7,318	19,095
Net Amounts Presented in the Statement of Income, Derivative Liabilities		$ 2,963
Net Amount, Derivative Liabilities	$ (3,080)