Derivatives (Offsetting Derivative Assets and Liabilities Subject to Master Netting Arrangements) (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Gross Amounts Recognized, Derivative Assets	$ 26,558	$ 16,167
Gross Amounts Offset in the Statement of Income, Derivative Assets	(26,405)	(12,842)
Net Amounts Presented in the Statement of Income, Derivative Assets	153	3,325
Gross Amounts Not Offset in the Statement of Income - Financial Instruments, Derivative Assets	153	1,846
Net Amounts Presented in the Statement of Income, Derivative Assets		1,479
Gross Amounts Recognized, Derivative Liabilities	51,833	23,811
Gross Amounts Offset in the Statement of Income, Derivative Liabilities	(41,325)	(21,651)
Net Amounts Presented in the Statement of Income, Derivative Liabilities	10,508	2,160
Gross Amounts Not Offset in the Statement of Income - Financial Instruments, Derivative Liabilities	153	1,846
Gross Amounts Not offset in the Statement of Income - Cash Collateral, Derivative Liabilities	15,304	2,871
Net Amounts Presented in the Statement of Income, Derivative Liabilities	$ (4,949)	$ (2,557)